sus ainabili y
A icle
Towa d Sus ainable Managemen : 2D Modelling o a
Sel -Cleaning Sys em o Imp o e Geome y in F on
o he Flushing Ga e
Luis Ca los Ruiloba 1, Manuel Gómez 2, Beniamino Russo 1, Gyewoon Choi 3and
Dongwoo Jang 3,*ID
1SUEZ Ad anced Solu ions, U ban D ainage Di ec ion, 48 Passeig Zona F anca, 08038 Ba celona, Spain;
[email p o ec ed] (L.C.R.); b [email protected] (B.R.)
2Flumen Resea ch Ins i u e, Technical Uni e si y o Ca alonia—Ba celona Tech, Jo di Gi ona 1-3,
08034 Ba celona, Spain; [email p o ec ed]
3Depa men o Ci il & En i onmen al Enginee ing, Incheon Na ional Uni e si y, Incheon 22012, Ko ea;
[email p o ec ed]
*Co espondence: [email p o ec ed]; Tel.: +82-32-835-4760; Fax: +82-32-851-5730
Recei ed: 11 Feb ua y 2018; Accep ed: 7 Ma ch 2018; Published: 8 Ma ch 2018
Abs ac :
This pape aims o show how nume ical modelling based on 2D SWE can be used o analyze
he cleaning e ec i eness o lushing wa es in s o m anks. The case s udy unde conside a ion
is an exis ing s o m ank loca ed in Badalona, a municipali y o Ba celona, Spain. S o m ank
cleaning sys ems a e c i ical ea u es ha mus be ca e ully add essed. I no app op ia ely add essed,
ope a ion and main enance wo k cos s can d as ically inc ease. The e a e nume ous cu en ly
a ailable echnologies o cleaning s o age anks. Howe e , no speci ic guide on his ield has been
iden i ied. Re e ences a e p o ided by he manu ac u e s h ough hei comme cial ca alogues.
Gene ally, his in o ma ion is no based on expe imen al o nume ical expe iences o esul s ha e no
been published in he li e a u e o scien i ic pape s. In his s udy, a public domain so wa e (IBER)
was used o de elop 2D hyd aulic analysis o he selec ed ank. The esul s ob ained show how he
phenomenon o eci cula ion is ac ing in some a eas o he lane. This implies a dissipa ion o ene gy,
hus causing di icul ies in e ms o cleaning p ocedu es. Fu he mo e, wo new scena ios ha e
been es ed o de e mine how a di e en lane wid h migh a ec hyd odynamic beha io . A newly
sugges ed geome y o he exis ing lane o he ank is p oposed by using he nume ical modeling
so wa e. The p oposed geome y in he cu en pilo ank achie es highe eloci ies and a oids
eci cula ion a eas. The esul s demons a e ha nume ical modelling o hese ypes o p ocesses
is possible wi h he compu e models a ailable (comme cial codes) and can be used o op imize
cleaning sys em design.
Keywo ds:
2D modelling; cleaning sys em; lushing sys em; eci cula ion; e en ion ank; s o m
ank; IBER
1. In oduc ion
Clima e change is leading o an inc ease in ex eme wea he condi ions a ound he wo ld. One
example is pa e ns o ex eme ain all. This challenges he cu en sewe sys em, no leas because an
inc ease in ain in ensi y o 40% o 60% will dec ease he e u n pe iod o looding e en s [1].
A g ow h in u baniza ion has led o an inc ease in he use o s o age anks, bo h o mi iga e
looding p oblems and o educe discha ge o ecei ing media (known as CSOs, o Combined Sewe
O e lows, in he case o combined sewe s) [2–4].
Sus ainabili y 2018,10, 745; doi:10.3390/su10030745 www.mdpi.com/jou nal/sus ainabili y
Sus ainabili y 2018,10, 745 2 o 12
I de ained wa e is ca ied di ec ly back in o he sewe age sys em, mos o he se led ma e ial
will emain and build up in he ank. Once es ablished, ank sedimen deposi s a e di icul o elimina e,
e en wi h p essu e cleaning equipmen . Such deposi s will hen ake up s o age capaci y [1].
By keeping he hea ily pollu ed wa e e ained in he anks, ecei ing bodies such as i e s and
beaches a e p o ec ed om o e lowing sedimen ac ions and he pollu an loads.
I is hus impe a i e o ake ca e o he cleaning p ocedu e inside he ank whe e he e ained
pollu ed ma e ial will be s o ed un il comp ehensi e cleaning [5–8].
Washing e iciency is dependen on s o m wa e ank design. S o m wa e anks a e o en buil
ou o conc e e, a lexible ma e ial which may assume many o ms o i he spaces a ailable [1].
The goal o his s udy is wo old: o ocus on imp o ing he geome y on he begging o he lane
and o analyze whe he a sel -cleaning sys em can wo k be e a he s a ing poin .
The cu en pilo case sys em consis s o a lushing ga e sys em. This mechanism ies o
ep oduce a dam b eak, in which a s o age chambe is illed by clean wa e (Figu e 1) and a powe ul
lushing wa e is p oduced o emo e he sedimen s o e he lane ollowing a sudden opening o he
lushing ga e.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 2 o 12
I de ained wa e is ca ied di ec ly back in o he sewe age sys em, mos o he se led ma e ial
will emain and build up in he ank. Once es ablished, ank sedimen deposi s a e di icul o
elimina e, e en wi h p essu e cleaning equipmen . Such deposi s will hen ake up s o age capaci y
[1].
By keeping he hea ily pollu ed wa e e ained in he anks, ecei ing bodies such as i e s and
beaches a e p o ec ed om o e lowing sedimen ac ions and he pollu an loads.
I is hus impe a i e o ake ca e o he cleaning p ocedu e inside he ank whe e he e ained
pollu ed ma e ial will be s o ed un il comp ehensi e cleaning [5–8].
Washing e iciency is dependen on s o m wa e ank design. S o m wa e anks a e o en buil
ou o conc e e, a lexible ma e ial which may assume many o ms o i he spaces a ailable [1].
The goal o his s udy is wo old: o ocus on imp o ing he geome y on he begging o he lane
and o analyze whe he a sel -cleaning sys em can wo k be e a he s a ing poin .
The cu en pilo case sys em consis s o a lushing ga e sys em. This mechanism ies o
ep oduce a dam b eak, in which a s o age chambe is illed by clean wa e (Figu e 1) and a powe ul
lushing wa e is p oduced o emo e he sedimen s o e he lane ollowing a sudden opening o he
lushing ga e.
Figu e 1. S o age chambe s o he Es ella s o m ank wi h a lushing ga e cleaning sys em.
Some e e ences ha e been ound ega ding he e ec s o lushing wa es p oduced by lushing
ga es in sewe pipes on he sedimen bed [9–13]. This esea ch p oposed designs o passi e
au oma ic lushing sys ems ins alled in each es bed and ha sewe cleaning can be ca ied ou by
lushing de ices able o discha ge a g ea olume o wa e du ing a sho pe iod o ime. The esul s
o nume ical modeling o sedimen lushing in a combined sewe each a e he ein p esen ed.
Some o hese s udies p oduced esea ch esul s ha could be used o be e unde s and and
design s o m anks cleaning sys ems based on lashing wa es in lushing lanes. O he s udies we e
conce ned wi h he cha ac e iza ion o sel -cleaning condi ions in sewe s and aimed o de elop sewe
design guidelines. Pisano e al. (1998) and Campisano e al. (2008) emphasize how heo e ical s udies
gene ally ail o conside pa icle cohesion, a ac o which can signi ican ly impac he ene gy
equi ed o sedimen mobiliza ion [14,15]. They also unde line he need o calcula e minimum low
eloci y o bed shea s ess o each pipe o assess he sewe ’s sel -cleaning.
2D modelling has hus been unde aken o s udy he in luence o lane wid h whe e he s o age
chambe and lushing ga e ha e ixed condi ions o dimensions. Tes ing was done using mul iple
simula ions o a oid sedimen p oblems ha could no be cleaned by he au oma ic sys em o he
Figu e 1. S o age chambe s o he Es ella s o m ank wi h a lushing ga e cleaning sys em.
Some e e ences ha e been ound ega ding he e ec s o lushing wa es p oduced by lushing
ga es in sewe pipes on he sedimen bed [
9
–
13
]. This esea ch p oposed designs o passi e au oma ic
lushing sys ems ins alled in each es bed and ha sewe cleaning can be ca ied ou by lushing
de ices able o discha ge a g ea olume o wa e du ing a sho pe iod o ime. The esul s o
nume ical modeling o sedimen lushing in a combined sewe each a e he ein p esen ed.
Some o hese s udies p oduced esea ch esul s ha could be used o be e unde s and and
design s o m anks cleaning sys ems based on lashing wa es in lushing lanes. O he s udies we e
conce ned wi h he cha ac e iza ion o sel -cleaning condi ions in sewe s and aimed o de elop sewe
design guidelines. Pisano e al. (1998) and Campisano e al. (2008) emphasize how heo e ical s udies
gene ally ail o conside pa icle cohesion, a ac o which can signi ican ly impac he ene gy equi ed
o sedimen mobiliza ion [
14
,
15
]. They also unde line he need o calcula e minimum low eloci y o
bed shea s ess o each pipe o assess he sewe ’s sel -cleaning.
2D modelling has hus been unde aken o s udy he in luence o lane wid h whe e he s o age
chambe and lushing ga e ha e ixed condi ions o dimensions. Tes ing was done using mul iple
simula ions o a oid sedimen p oblems ha could no be cleaned by he au oma ic sys em o he
Sus ainabili y 2018,10, 745 3 o 12
lushing ga e sys em. I was unde aken in he “La Es ella” de en ion ank in Badalona, a me opoli an
a ea o Ba celona. A e analyzing he hyd odynamics beha io o he lushing wa e, a new geome ical
imp o emen o he cu en scena io has been p oposed o achie e be e cleaning esul s and o
minimize main enance cos s when manual cleaning is equi ed. Tha also implies a human isk
because hese in as uc u es a e con ined spaces.
2. Theo e ical Backg ound
2.1. Ma hema ical Equa ions
To desc ibe he beha io o he luid o e he lane in he pilo e en ion ank, 2D Shallow Wa e
Equa ions (2D-SWE) ha e been used. Based on conse a ion o mass and momen um laws, 2D
Sain -Venan equa ions ha e been de i ed. Pa icula izing o a New onian and iso opic luid and
desc ibing he a e age a iables in sho - ime inc emen s while conside ing u bulen luc ua ion,
Na ie -S okes equa ions a e speci ied in he Reynolds equa ions.
The Reynolds A e aged Na ie -S okes (RANS) equa ions a e deduc ed by applying mass and
momen um conse a ion. A wo-dimensional exp ession could be eached in eg a ing he e ical
dimension. The mos p edominan di ec ions a e shown in he ollowing equa ions:
∂h
∂ +∂(hu1)
∂x1
+∂(hu2)
∂x2
=0 (1)
∂
∂ (hu1)+∂
∂x1hu2
1+gh2
2+∂
∂x2
(hu1u2)=S0,x1−S ,x1(2)
∂
∂ (hu2)+∂
∂x1
(hu1u2)+∂
∂x2hu2
2+gh2
2=S0,x2−S ,x2(3)
whe e u
1
and u
2
a e eloci y componen s in eg a ed wi h dep h; x
1
and x
2
a e s udied plain di ec ions;
his wa e dep h; and S0,S a e he bed slopes in he s udied di ec ions.
Local accele a ion o Sain -Venan is shown in Equa ion (4).
∂u1
∂ &∂u2
∂ (4)
These ac o s desc ibe in a ixed poin he a ia ion in ime. Con ec i e accele a ion is shown in
Equa ion (5).
u1
∂u1
∂x1
,u1
∂u2
∂x1
,u2
∂u1
∂x2
&u2
∂u2
∂x2
(5)
T anspo wi h he lux as a eloci y g adien is ep esen ed in he las e ms. The highe he
Reynolds numbe , he mo e signi ican hese ac o s become due o ine ial and iscosi y o ces.
2.2. Nume ical So wa e o he Analysis
IBER, de eloped by he Wa e and En i onmen al Enginee ing G oup, GEAMA (Uni e si y o
A Co uña), he Flumen esea ch Ins i u e (Technical Uni e si y o Ca alonia, UPC, and In e na ional
Cen e o Nume ical Me hods in Enginee ing, CIMNE), was selec ed as he nume ical so wa e o es
simula ions in he e en ion ank. IBER’s anges o applica ion co e i e hyd odynamics, dam-b eak
simula ion, lood zones e alua ion, sedimen anspo calcula ion, and wa e low in es ua ies [16].
IBER con ains 3 di e en compu a ional modules, including hyd odynamic, u bulence, and a
sedimen anspo module ( he wo las modules we e no used in he p esen essay). Sain -Venan
equa ions will be sol ed in a ini e olume o s uc u ed o non-s uc u ed mesh (acco ding o he
use ’s choice) o med by iangula o quad ila e al elemen s.
Sus ainabili y 2018,10, 745 4 o 12
3. Ma e ials and Me hods
3.1. Desc ip ion o he Case S udy
The La Es ella s o m ank is in Badalona, a municipali y o he immedia e no h eas o Ba celona
in Ca alonia, Spain. I s o al s o age olume is 30.000 m
3
and he main pu pose o he ank is o
a oid looding and educe CSO p oblems su ounding Badalona beach. I has 12 lanes all o di e en
leng hs due o i s i egula layou shape (Figu e 2). The a e age wid h o each lane is 5 m, while he
longi udinal slope is 1%.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 4 o 12
3. Ma e ials and Me hods
3.1. Desc ip ion o he Case S udy
The La Es ella s o m ank is in Badalona, a municipali y o he immedia e no h eas o
Ba celona in Ca alonia, Spain. I s o al s o age olume is 30.000 m3 and he main pu pose o he ank
is o a oid looding and educe CSO p oblems su ounding Badalona beach. I has 12 lanes all o
di e en leng hs due o i s i egula layou shape (Figu e 2). The a e age wid h o each lane is 5 m,
while he longi udinal slope is 1%.
Figu e 2. Inside pic u e o he Es ella s o m ank in Badalona and he s udied lane.
The pilo ank’s sel -cleaning sys em consis s o a lushing ga e sys em in which a i s s o age
chambe is illed wi h clean wa e . A powe ul lushing wa e p oduced by he opening o he lushing
ga e hen s a s o clean he lane. In Figu e 3, a lushing ga e is shown a he beginning o he cleaning
p ocess.
Figu e 3. Flushing ga e opening in a cleaning ope a ion.
3.2. Hyd aulic and Sedimen Modelling
3.2.1. IBER Gene al Desc ip ion
IBER is a public domain so wa e de eloped a he Technical Uni e si y o Ca alonia (UPC), in
Ba celona, by he Flumen Resea ch Ins i u e and i was used o make a 2D hyd aulic analysis. IBER’s
code is a ull 2D hyd odynamic code including sedimen anspo capabili ies (bed load and
suspended load) [17].
Figu e 2. Inside pic u e o he Es ella s o m ank in Badalona and he s udied lane.
The pilo ank’s sel -cleaning sys em consis s o a lushing ga e sys em in which a i s s o age
chambe is illed wi h clean wa e . A powe ul lushing wa e p oduced by he opening o he lushing
ga e hen s a s o clean he lane. In Figu e 3, a lushing ga e is shown a he beginning o he
cleaning p ocess.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 4 o 12
3. Ma e ials and Me hods
3.1. Desc ip ion o he Case S udy
The La Es ella s o m ank is in Badalona, a municipali y o he immedia e no h eas o
Ba celona in Ca alonia, Spain. I s o al s o age olume is 30.000 m3 and he main pu pose o he ank
is o a oid looding and educe CSO p oblems su ounding Badalona beach. I has 12 lanes all o
di e en leng hs due o i s i egula layou shape (Figu e 2). The a e age wid h o each lane is 5 m,
while he longi udinal slope is 1%.
Figu e 2. Inside pic u e o he Es ella s o m ank in Badalona and he s udied lane.
The pilo ank’s sel -cleaning sys em consis s o a lushing ga e sys em in which a i s s o age
chambe is illed wi h clean wa e . A powe ul lushing wa e p oduced by he opening o he lushing
ga e hen s a s o clean he lane. In Figu e 3, a lushing ga e is shown a he beginning o he cleaning
p ocess.
Figu e 3. Flushing ga e opening in a cleaning ope a ion.
3.2. Hyd aulic and Sedimen Modelling
3.2.1. IBER Gene al Desc ip ion
IBER is a public domain so wa e de eloped a he Technical Uni e si y o Ca alonia (UPC), in
Ba celona, by he Flumen Resea ch Ins i u e and i was used o make a 2D hyd aulic analysis. IBER’s
code is a ull 2D hyd odynamic code including sedimen anspo capabili ies (bed load and
suspended load) [17].
Figu e 3. Flushing ga e opening in a cleaning ope a ion.
3.2. Hyd aulic and Sedimen Modelling
3.2.1. IBER Gene al Desc ip ion
IBER is a public domain so wa e de eloped a he Technical Uni e si y o Ca alonia (UPC),
in Ba celona, by he Flumen Resea ch Ins i u e and i was used o make a 2D hyd aulic analysis.
Sus ainabili y 2018,10, 745 5 o 12
IBER’s code is a ull 2D hyd odynamic code including sedimen anspo capabili ies (bed load and
suspended load) [17].
The Hyd odynamic module is based on he 2D ull Sain Venan equa ions, inco po a ing an
explici ini e olume scheme on s uc u ed o uns uc u ed meshes ( iangula o quad ila e al).
I hus sol es all ypes o lows, including u bulen e ec s and bed e olu ion caused by sedimen
anspo . IBER has a use - iendly in e ace o p e-and pos -p ocessing, and i has been e i ied and
alida ed ia analy ical solu ions, o he models, labo a o y es ing, and ield measu emen s. I is he
model used by he Spanish wa e adminis a ion o lood isk analysis.
3.2.2. Model Se up and Hyd aulic Modelling
The mos impo an geome ical elemen s o s udy eci cula ion in he i s me e s o he lane a e
he s o age chambe ups eam o he ga e, he loca ion and dimensions o he ga e, and he i s me e s
o he lane i sel . I is impo an o highligh , as shown in Figu e 4, ha he lushing ga e is no ully
symme ical in he La Es ella e en ion ank, and his aspec was aken in o conside a ion du ing he
simula ion p ocess.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 5 o 12
The Hyd odynamic module is based on he 2D ull Sain Venan equa ions, inco po a ing an
explici ini e olume scheme on s uc u ed o uns uc u ed meshes ( iangula o quad ila e al). I
hus sol es all ypes o lows, including u bulen e ec s and bed e olu ion caused by sedimen
anspo . IBER has a use - iendly in e ace o p e-and pos -p ocessing, and i has been e i ied and
alida ed ia analy ical solu ions, o he models, labo a o y es ing, and ield measu emen s. I is he
model used by he Spanish wa e adminis a ion o lood isk analysis.
3.2.2. Model Se up and Hyd aulic Modelling
The mos impo an geome ical elemen s o s udy eci cula ion in he i s me e s o he lane
a e he s o age chambe ups eam o he ga e, he loca ion and dimensions o he ga e, and he i s
me e s o he lane i sel . I is impo an o highligh , as shown in Figu e 4, ha he lushing ga e is no
ully symme ical in he La Es ella e en ion ank, and his aspec was aken in o conside a ion
du ing he simula ion p ocess.
(a) (b)
Figu e 4. Ga e dimensions: (a) on al iew, (b) la e al iew.
Hyd odynamics simula ions we e ca ied ou wi h he cu en geome y [18]. Analyzing he
maximum eloci ies a e a lushing e en , i was clea ha he highes eloci ies occu in he middle
o he lane. Lowe eloci ies occu ega ding he side walls. Values each hei lowes esul s (below
1 m/s) in he le co ne o he lane. This was an icipa ed, due o he non-symme ic loca ion o he
lushing ga e (Figu e 5).
Figu e 5. Maximum eloci y dis ibu ion on he lane.
As a esul , a mo e de ailed s udy o he co ne s was unde aken, and he eci cula ion a eas
ha e been de ec ed analyzing he ec o di ec ions o he eloci y (Figu e 6). These ec o s clea ly
show how, in hese eci cula ion a eas, eloci y has opposi e di ec ion om he low di ec ion. These
changes in wa e di ec ion cause swi ls in he eci cula ion a eas ha imply ene gy dissipa ion and
p oblems in e ms o he cleaning p ocess.
Figu e 4. Ga e dimensions: (a) on al iew, (b) la e al iew.
Hyd odynamics simula ions we e ca ied ou wi h he cu en geome y [
18
]. Analyzing he
maximum eloci ies a e a lushing e en , i was clea ha he highes eloci ies occu in he middle
o he lane. Lowe eloci ies occu ega ding he side walls. Values each hei lowes esul s (below
1 m/s) in he le co ne o he lane. This was an icipa ed, due o he non-symme ic loca ion o he
lushing ga e (Figu e 5).
Sus ainabili y 2018, 10, x FOR PEER REVIEW 5 o 12
The Hyd odynamic module is based on he 2D ull Sain Venan equa ions, inco po a ing an
explici ini e olume scheme on s uc u ed o uns uc u ed meshes ( iangula o quad ila e al). I
hus sol es all ypes o lows, including u bulen e ec s and bed e olu ion caused by sedimen
anspo . IBER has a use - iendly in e ace o p e-and pos -p ocessing, and i has been e i ied and
alida ed ia analy ical solu ions, o he models, labo a o y es ing, and ield measu emen s. I is he
model used by he Spanish wa e adminis a ion o lood isk analysis.
3.2.2. Model Se up and Hyd aulic Modelling
The mos impo an geome ical elemen s o s udy eci cula ion in he i s me e s o he lane
a e he s o age chambe ups eam o he ga e, he loca ion and dimensions o he ga e, and he i s
me e s o he lane i sel . I is impo an o highligh , as shown in Figu e 4, ha he lushing ga e is no
ully symme ical in he La Es ella e en ion ank, and his aspec was aken in o conside a ion
du ing he simula ion p ocess.
(a) (b)
Figu e 4. Ga e dimensions: (a) on al iew, (b) la e al iew.
Hyd odynamics simula ions we e ca ied ou wi h he cu en geome y [18]. Analyzing he
maximum eloci ies a e a lushing e en , i was clea ha he highes eloci ies occu in he middle
o he lane. Lowe eloci ies occu ega ding he side walls. Values each hei lowes esul s (below
1 m/s) in he le co ne o he lane. This was an icipa ed, due o he non-symme ic loca ion o he
lushing ga e (Figu e 5).
Figu e 5. Maximum eloci y dis ibu ion on he lane.
As a esul , a mo e de ailed s udy o he co ne s was unde aken, and he eci cula ion a eas
ha e been de ec ed analyzing he ec o di ec ions o he eloci y (Figu e 6). These ec o s clea ly
show how, in hese eci cula ion a eas, eloci y has opposi e di ec ion om he low di ec ion. These
changes in wa e di ec ion cause swi ls in he eci cula ion a eas ha imply ene gy dissipa ion and
p oblems in e ms o he cleaning p ocess.
Figu e 5. Maximum eloci y dis ibu ion on he lane.
As a esul , a mo e de ailed s udy o he co ne s was unde aken, and he eci cula ion a eas
ha e been de ec ed analyzing he ec o di ec ions o he eloci y (Figu e 6). These ec o s clea ly
show how, in hese eci cula ion a eas, eloci y has opposi e di ec ion om he low di ec ion. These

Sus ainabili y 2018,10, 745 6 o 12
changes in wa e di ec ion cause swi ls in he eci cula ion a eas ha imply ene gy dissipa ion and
p oblems in e ms o he cleaning p ocess.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 6 o 12
Figu e 6. Flow eloci y ec o s in a co ne nex o he ga e.
Using he so wa e, c i ical bed shea s esses a e also calcula ed o analyze which a eas could
be c i ical in e ms o sedimen anspo .
In Figu e 7, a eas wi h shea s esses below he c i ical alue o 2 N/m2 (sugges ed by Ashley
and Cab ee, 1992 [19]) a e shown. This a ea co esponds wi h he sides o he lane, whe e he
eci cula ion phenomenon has been de ec ed. These bed shea s ess alues indica e e osion
di icul ies.
(a)
(b)
(c)
Figu e 7. Rep esen a ion o a eas wi h shea s ess below he e e ence alues o 2 N/m2: (a) Time s ep
1, (b) Time s ep 6, (c) Time s ep 12.
4. Sugges ion o New Geome ies
4.1. Tes ing Di e en Geome ies
To s udy how he wid h o he lane a ec s his eci cula ion phenomenon, he cu en geome y
(scena io 1) o he lane has been compa ed wi h wo di e en scena ios. On he one hand, a la ge
Figu e 6. Flow eloci y ec o s in a co ne nex o he ga e.
Using he so wa e, c i ical bed shea s esses a e also calcula ed o analyze which a eas could be
c i ical in e ms o sedimen anspo .
In Figu e 7, a eas wi h shea s esses below he c i ical alue o 2 N/m
2
(sugges ed by Ashley and
Cab ee, 1992 [
19
]) a e shown. This a ea co esponds wi h he sides o he lane, whe e he eci cula ion
phenomenon has been de ec ed. These bed shea s ess alues indica e e osion di icul ies.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 6 o 12
Figu e 6. Flow eloci y ec o s in a co ne nex o he ga e.
Using he so wa e, c i ical bed shea s esses a e also calcula ed o analyze which a eas could
be c i ical in e ms o sedimen anspo .
In Figu e 7, a eas wi h shea s esses below he c i ical alue o 2 N/m2 (sugges ed by Ashley
and Cab ee, 1992 [19]) a e shown. This a ea co esponds wi h he sides o he lane, whe e he
eci cula ion phenomenon has been de ec ed. These bed shea s ess alues indica e e osion
di icul ies.
(a)
(b)
(c)
Figu e 7. Rep esen a ion o a eas wi h shea s ess below he e e ence alues o 2 N/m2: (a) Time s ep
1, (b) Time s ep 6, (c) Time s ep 12.
4. Sugges ion o New Geome ies
4.1. Tes ing Di e en Geome ies
To s udy how he wid h o he lane a ec s his eci cula ion phenomenon, he cu en geome y
(scena io 1) o he lane has been compa ed wi h wo di e en scena ios. On he one hand, a la ge
Figu e 7.
Rep esen a ion o a eas wi h shea s ess below he e e ence alues o 2 N/m
2
: (
a
) Time
s ep 1, (b) Time s ep 6, (c) Time s ep 12.
Sus ainabili y 2018,10, 745 7 o 12
4. Sugges ion o New Geome ies
4.1. Tes ing Di e en Geome ies
To s udy how he wid h o he lane a ec s his eci cula ion phenomenon, he cu en geome y
(scena io 1) o he lane has been compa ed wi h wo di e en scena ios. On he one hand, a la ge
sec ion in wid h has been es ed (scena io 2), and on he o he hand, a hinne lane, con igu ed o ha e
he same wid h as he lushing ga e (scena io 3) has been es ed o s udy wo opposi e scena ios.
Lane leng h has been educed om 55 m o 19 m o dec ease he compu a ional nume ical cos ,
o de ine a mo e de ailed mesh o e he lane, and o ob ain he mo e de ined esul s necessa y o a
p ope s udy o he eci cula ion phenomenon. The cu en geome y o he lane is abou 4.8 m in
wid h. The ga e is no loca ed in a symme ic posi ion and has a wid h o 2.8 m.
The Manning coe icien used on all su aces is 0.015 since lanes and walls a e conc e e. A plane
iew o he pilo e en ion ank lane is shown in Figu e 8. Whe e he blue colo ep esen s he de ined
lines in he model o c ea e he di e en su aces (pu ple line) whe e he mesh is de ined.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 7 o 12
sec ion in wid h has been es ed (scena io 2), and on he o he hand, a hinne lane, con igu ed o
ha e he same wid h as he lushing ga e (scena io 3) has been es ed o s udy wo opposi e scena ios.
Lane leng h has been educed om 55 m o 19 m o dec ease he compu a ional nume ical cos ,
o de ine a mo e de ailed mesh o e he lane, and o ob ain he mo e de ined esul s necessa y o a
p ope s udy o he eci cula ion phenomenon. The cu en geome y o he lane is abou 4.8 m in
wid h. The ga e is no loca ed in a symme ic posi ion and has a wid h o 2.8 m.
The Manning coe icien used on all su aces is 0.015 since lanes and walls a e conc e e. A plane
iew o he pilo e en ion ank lane is shown in Figu e 8. Whe e he blue colo ep esen s he de ined
lines in he model o c ea e he di e en su aces (pu ple line) whe e he mesh is de ined.
Figu e 8. Geome y o he cu en lane in he pilo e en ion ank.
Table 1 shows he cha ac e is ics o he selec ed scena ios:
Table 1. Cha ac e is ics o he selec ed scena ios o be es ed.
Scena io Lane Cha ac e is ics Manning Coe .
Leng h (m) Wid h (m)
1 19 4.8 0.015
2 19 6.8 0.015
3 19 2.8 0.015
A simula ion wi h he same ini ial condi ions was unde aken o compa e he scena ios, and
eloci y e olu ion in 6 lane poin s o each s uc u e was s udied. The selec ed poin s we e 0.5 and 1.5
m in on o he lushing ga e, in he middle o he lane, and ouching he le and igh side walls.
The selec ed measu ing poin s a e shown in Figu e 9 (blue do s).
Figu e 9. Selec ed poin s o s udy eloci y e olu ion in he x di ec ion.
In he cu en scena io, he highes eloci ies eached we e in he middle o he lane. A he sides
i was clea ha eloci ies a e lowe , e en aking on nega i es alues (due o he eci cula ion
phenomenon). The mos p oblema ic side p o ed o be on he le and his was due o he non-
symme y o he lushing ga e loca ion.
E alua ion o eloci y in he x di ec ion o selec ed scena ios is p esen ed below. Figu e 10
demons a es ha sedimen a ion occu s in eci cula ion a eas whe e eloci y is in he opposi e
di ec ion o low.
E alua ion o eloci y in he x di ec ion o a wide scena io is shown in Figu e 11. Whe e lane
wid h is inc eased, eloci y ec o is always opposi e o low di ec ion when wa e eaches he wall
sides. As was expec ed, using his kind o geome y inc eases he eci cula ion a eas. Mo eo e ,
ma e ial will be accumula ed in on o he lushing ga e due o cons an nega i e eloci ies.
Figu e 8. Geome y o he cu en lane in he pilo e en ion ank.
Table 1shows he cha ac e is ics o he selec ed scena ios:
Table 1. Cha ac e is ics o he selec ed scena ios o be es ed.
Scena io Lane Cha ac e is ics Manning Coe .
Leng h (m) Wid h (m)
1 19 4.8 0.015
2 19 6.8 0.015
3 19 2.8 0.015
A simula ion wi h he same ini ial condi ions was unde aken o compa e he scena ios,
and eloci y e olu ion in 6 lane poin s o each s uc u e was s udied. The selec ed poin s we e
0.5 and 1.5 m in on o he lushing ga e, in he middle o he lane, and ouching he le and igh
side walls. The selec ed measu ing poin s a e shown in Figu e 9(blue do s).
Sus ainabili y 2018, 10, x FOR PEER REVIEW 7 o 12
sec ion in wid h has been es ed (scena io 2), and on he o he hand, a hinne lane, con igu ed o
ha e he same wid h as he lushing ga e (scena io 3) has been es ed o s udy wo opposi e scena ios.
Lane leng h has been educed om 55 m o 19 m o dec ease he compu a ional nume ical cos ,
o de ine a mo e de ailed mesh o e he lane, and o ob ain he mo e de ined esul s necessa y o a
p ope s udy o he eci cula ion phenomenon. The cu en geome y o he lane is abou 4.8 m in
wid h. The ga e is no loca ed in a symme ic posi ion and has a wid h o 2.8 m.
The Manning coe icien used on all su aces is 0.015 since lanes and walls a e conc e e. A plane
iew o he pilo e en ion ank lane is shown in Figu e 8. Whe e he blue colo ep esen s he de ined
lines in he model o c ea e he di e en su aces (pu ple line) whe e he mesh is de ined.
Figu e 8. Geome y o he cu en lane in he pilo e en ion ank.
Table 1 shows he cha ac e is ics o he selec ed scena ios:
Table 1. Cha ac e is ics o he selec ed scena ios o be es ed.
Scena io Lane Cha ac e is ics Manning Coe .
Leng h (m) Wid h (m)
1 19 4.8 0.015
2 19 6.8 0.015
3 19 2.8 0.015
A simula ion wi h he same ini ial condi ions was unde aken o compa e he scena ios, and
eloci y e olu ion in 6 lane poin s o each s uc u e was s udied. The selec ed poin s we e 0.5 and 1.5
m in on o he lushing ga e, in he middle o he lane, and ouching he le and igh side walls.
The selec ed measu ing poin s a e shown in Figu e 9 (blue do s).
Figu e 9. Selec ed poin s o s udy eloci y e olu ion in he x di ec ion.
In he cu en scena io, he highes eloci ies eached we e in he middle o he lane. A he sides
i was clea ha eloci ies a e lowe , e en aking on nega i es alues (due o he eci cula ion
phenomenon). The mos p oblema ic side p o ed o be on he le and his was due o he non-
symme y o he lushing ga e loca ion.
E alua ion o eloci y in he x di ec ion o selec ed scena ios is p esen ed below. Figu e 10
demons a es ha sedimen a ion occu s in eci cula ion a eas whe e eloci y is in he opposi e
di ec ion o low.
E alua ion o eloci y in he x di ec ion o a wide scena io is shown in Figu e 11. Whe e lane
wid h is inc eased, eloci y ec o is always opposi e o low di ec ion when wa e eaches he wall
sides. As was expec ed, using his kind o geome y inc eases he eci cula ion a eas. Mo eo e ,
ma e ial will be accumula ed in on o he lushing ga e due o cons an nega i e eloci ies.
Figu e 9. Selec ed poin s o s udy eloci y e olu ion in he xdi ec ion.
In he cu en scena io, he highes eloci ies eached we e in he middle o he lane. A he
sides i was clea ha eloci ies a e lowe , e en aking on nega i es alues (due o he eci cula ion
phenomenon). The mos p oblema ic side p o ed o be on he le and his was due o he
non-symme y o he lushing ga e loca ion.
Sus ainabili y 2018,10, 745 8 o 12
E alua ion o eloci y in he xdi ec ion o selec ed scena ios is p esen ed below. Figu e 10
demons a es ha sedimen a ion occu s in eci cula ion a eas whe e eloci y is in he opposi e di ec ion
o low.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 8 o 12
(a) (b)
Figu e 10. E alua ion o eloci y in he x di ec ion o scena io 1: (a) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
(a) (b)
Figu e 11. E alua ion o eloci y in he x di ec ion o scena io 2: (a) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
Finally, esul s ob ained in he na owe scena io (Figu e 12) demons a e highe sides eloci ies
han in he o he scena ios. Fu he mo e, beha io is mo e homogenous in he wid h o he lane,
which implies i is he mos e icien lushing wa e o he cleaning sys em. Veloci ies we e highe
han 2 m/s o mo e han 8 s in all lanes. This is highe ha he eloci y ecommended o ensu e sel -
cleaning in sewe s. Fu he mo e, no nega i e eloci ies appea in he x di ec ion, which means no
eci cula ion phenomena occu s using his geome y.
(a) (b)
Figu e 12. E alua ion o eloci y in he x di ec ion o scena io 3: (a) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
Figu e 10.
E alua ion o eloci y in he x di ec ion o scena io 1: (
a
) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
E alua ion o eloci y in he xdi ec ion o a wide scena io is shown in Figu e 11. Whe e lane
wid h is inc eased, eloci y ec o is always opposi e o low di ec ion when wa e eaches he wall
sides. As was expec ed, using his kind o geome y inc eases he eci cula ion a eas. Mo eo e ,
ma e ial will be accumula ed in on o he lushing ga e due o cons an nega i e eloci ies.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 8 o 12
(a) (b)
Figu e 10. E alua ion o eloci y in he x di ec ion o scena io 1: (a) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
(a) (b)
Figu e 11. E alua ion o eloci y in he x di ec ion o scena io 2: (a) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
Finally, esul s ob ained in he na owe scena io (Figu e 12) demons a e highe sides eloci ies
han in he o he scena ios. Fu he mo e, beha io is mo e homogenous in he wid h o he lane,
which implies i is he mos e icien lushing wa e o he cleaning sys em. Veloci ies we e highe
han 2 m/s o mo e han 8 s in all lanes. This is highe ha he eloci y ecommended o ensu e sel -
cleaning in sewe s. Fu he mo e, no nega i e eloci ies appea in he x di ec ion, which means no
eci cula ion phenomena occu s using his geome y.
(a) (b)
Figu e 12. E alua ion o eloci y in he x di ec ion o scena io 3: (a) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
Figu e 11.
E alua ion o eloci y in he x di ec ion o scena io 2: (
a
) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
Finally, esul s ob ained in he na owe scena io (Figu e 12) demons a e highe sides eloci ies
han in he o he scena ios. Fu he mo e, beha io is mo e homogenous in he wid h o he lane, which
implies i is he mos e icien lushing wa e o he cleaning sys em. Veloci ies we e highe han 2 m/s
o mo e han 8 s in all lanes. This is highe ha he eloci y ecommended o ensu e sel -cleaning in
sewe s. Fu he mo e, no nega i e eloci ies appea in he xdi ec ion, which means no eci cula ion
phenomena occu s using his geome y.
Sus ainabili y 2018,10, 745 9 o 12
Sus ainabili y 2018, 10, x FOR PEER REVIEW 8 o 12
(a) (b)
Figu e 10. E alua ion o eloci y in he x di ec ion o scena io 1: (a) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
(a) (b)
Figu e 11. E alua ion o eloci y in he x di ec ion o scena io 2: (a) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
Finally, esul s ob ained in he na owe scena io (Figu e 12) demons a e highe sides eloci ies
han in he o he scena ios. Fu he mo e, beha io is mo e homogenous in he wid h o he lane,
which implies i is he mos e icien lushing wa e o he cleaning sys em. Veloci ies we e highe
han 2 m/s o mo e han 8 s in all lanes. This is highe ha he eloci y ecommended o ensu e sel -
cleaning in sewe s. Fu he mo e, no nega i e eloci ies appea in he x di ec ion, which means no
eci cula ion phenomena occu s using his geome y.
(a) (b)
Figu e 12. E alua ion o eloci y in he x di ec ion o scena io 3: (a) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
Figu e 12.
E alua ion o eloci y in he x di ec ion o scena io 3: (
a
) 0.5 m poin s in on o he lushing
ga e, (b) 1.5 m poin s in on o he lushing ga e.
4.2. Modelling o he P oposed Geome y
Reci cula ion phenomenon basically occu s on he wall sides. I is impo an o ocus on he
los ene gy caused by eci cula ion o p e en deposi ion o ma e ial in hese a eas. Tes ing a ious
geome ies e eals ha a lane o he same wid h as he lushing ga e wo ks be e in p oducing a
homogenous lushing wa e han lanes wi h no eci cula ion a eas.
Fo his eason, he p oposed geome y o he Badalona s o m ank ills he eci cula ion a eas
wi h a conc e e slope o wingwall o p og essi ely d i e he ene gy wa e om he ga e wid h owa d
he lane wid h. In iew o he es ed geome ies’ ob ained esul s, a na ow wid h a he beginning
o he lane which p og essi ely d i es he low o he end o he eci cula ion zone is he p oposed
geome y (Figu e 13).
Sus ainabili y 2018, 10, x FOR PEER REVIEW 9 o 12
4.2. Modelling o he P oposed Geome y
Reci cula ion phenomenon basically occu s on he wall sides. I is impo an o ocus on he los
ene gy caused by eci cula ion o p e en deposi ion o ma e ial in hese a eas. Tes ing a ious
geome ies e eals ha a lane o he same wid h as he lushing ga e wo ks be e in p oducing a
homogenous lushing wa e han lanes wi h no eci cula ion a eas.
Fo his eason, he p oposed geome y o he Badalona s o m ank ills he eci cula ion a eas
wi h a conc e e slope o wingwall o p og essi ely d i e he ene gy wa e om he ga e wid h owa d
he lane wid h. In iew o he es ed geome ies’ ob ained esul s, a na ow wid h a he beginning o
he lane which p og essi ely d i es he low o he end o he eci cula ion zone is he p oposed
geome y (Figu e 13).
Figu e 13. P oposal o ac ua ion in on o he lushing ga e.
In Figu e 14, lane maximum eloci ies a e ep esen ed wi h he p oposed eloci y. The
maximum eloci y is 1.25 imes highe han he scena io es ed using he cu en geome y.
Figu e 14. Maximum eloci ies wi h he new geome y.
The e alua ion o eloci y in he x di ec ion is shown in Figu e 15 o compa e he p oposed
geome y wi h he cu en scena io (scena io 1 ep esen ed in Figu e 10):
(a) (b)
Figu e 15. E alua ion o eloci y in he x di ec ion o he p oposed geome y scena io: (a) 0.5 m poin s
in on o he lushing ga e, (b) 1.5 m poin s in on o he lushing ga e.
Figu e 13. P oposal o ac ua ion in on o he lushing ga e.
In Figu e 14, lane maximum eloci ies a e ep esen ed wi h he p oposed eloci y. The maximum
eloci y is 1.25 imes highe han he scena io es ed using he cu en geome y.
Sus ainabili y 2018, 10, x FOR PEER REVIEW 9 o 12
4.2. Modelling o he P oposed Geome y
Reci cula ion phenomenon basically occu s on he wall sides. I is impo an o ocus on he los
ene gy caused by eci cula ion o p e en deposi ion o ma e ial in hese a eas. Tes ing a ious
geome ies e eals ha a lane o he same wid h as he lushing ga e wo ks be e in p oducing a
homogenous lushing wa e han lanes wi h no eci cula ion a eas.
Fo his eason, he p oposed geome y o he Badalona s o m ank ills he eci cula ion a eas
wi h a conc e e slope o wingwall o p og essi ely d i e he ene gy wa e om he ga e wid h owa d
he lane wid h. In iew o he es ed geome ies’ ob ained esul s, a na ow wid h a he beginning o
he lane which p og essi ely d i es he low o he end o he eci cula ion zone is he p oposed
geome y (Figu e 13).
Figu e 13. P oposal o ac ua ion in on o he lushing ga e.
In Figu e 14, lane maximum eloci ies a e ep esen ed wi h he p oposed eloci y. The
maximum eloci y is 1.25 imes highe han he scena io es ed using he cu en geome y.
Figu e 14. Maximum eloci ies wi h he new geome y.
The e alua ion o eloci y in he x di ec ion is shown in Figu e 15 o compa e he p oposed
geome y wi h he cu en scena io (scena io 1 ep esen ed in Figu e 10):
(a) (b)
Figu e 15. E alua ion o eloci y in he x di ec ion o he p oposed geome y scena io: (a) 0.5 m poin s
in on o he lushing ga e, (b) 1.5 m poin s in on o he lushing ga e.
Figu e 14. Maximum eloci ies wi h he new geome y.
The e alua ion o eloci y in he x di ec ion is shown in Figu e 15 o compa e he p oposed
geome y wi h he cu en scena io (scena io 1 ep esen ed in Figu e 10):