Comprehensive and Fully Integrated. Research Program. SERF Increasing Scale and Applicability. (Shoreline Environmental Research Facility)

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1 Comprehensve and Fully Integrated Full-Scale Feld Research Program SERF Increasng Scale and Applcablty Controlled Feld Mesocosm (Shorelne Envronmental Research Faclty) Laboratory Texas A&M Unversty Temtope O. Ojo Asst. Research Scentst James Bonner Drector Increasng Expermental Control

2 Introducton 3-Dmensonal models may be needed to descrbe plume transport and sedment deposton. Droplet coalescence s not typcally ncorporated n 3-D models Process may be mportant n systems wth low dluton rates or large volume splls Transport Modelng conssts of two parts: Partcle transport Advecton-Dsperson equaton Droplet-sedment coagulaton Partcle Coagulaton netc equaton Based on Smoluchows s equaton Coagulaton effcency functons related to envronmental chemcal characterstcs (ph, onc strength, dspersant concentraton, ol vscosty, etc.) Prevous Research Vertcal transport model was developed and valdated for sedment transport (Bonner et al., 1994; Ernest et al., 1995). Batch studes demonstrated that dspersed ol has aggregaton behavor smlar to that of suspended cohesve sedment (Sterlng et al., 00)

3 Expermental-Laboratory How does chemcally-dspersed ol behave when nteractng wth ambent partcles? Very pertnent to coastal waters: hgh levels of slt, planton and other bologcal partcles, and are more-lely locatons for ol splls. Ol droplet fate depends on type of ambent partcle nteracton Determnng RPM vs. G m curve Power calculated from measured values P = Tω Mean shear velocty G m calculated from power G m = (P/μV) 1/

4 Expermental-Mesoscale Tan Characterzaton Impact of Oscllaton Frequency on Dsperson Coeffcents & Steady-state eddy dstrbutons Impact of Wave Heght on Vertcal Dsperson Investgatng effects of water temperature and wave energy Wave Tan Scalng

5 Wave Tan Scalng Testbed = Corpus Chrst Bay ---- Fr testbed Model system = SERF wave tan -Fr model Scalng factor Fr=[nertal force]/[gravty force] 0.5 = V/(g* L) 0.5 where g gravty, L s the wave length, V s the velocty or wave celerty Wave length for lnear waves Wave velocty Shear rate Power Dsspaton L = gt π L gt gt V = = = T π T π G m = P Vμ 0.5 P gm [ το] = G Vμ, = E C, = E C (1m ), = m area g area g crestwdth 3 s

6 Expermental-Feld Fxed Moble Remote Radar

7 Ponts to Note Collodal Ol TGLO Research Group Poneered Ths Important Concept Ol-n-Water Studes Dssolved (soluble) component of ol Collodal component of ol Ol-partcle aggregaton Mean shear rate (vertcal dsperson) had the greatest mpact on ol resurfacng Ol specfc gravty and collson effcency have comparable nfluence n ol resurfacng. Above a threshold value (3 ppm), ntal ol concentraton became the least sgnfcant nfluental factor mpactng dspersed ol resurfacng. Mxng Energy G m ~ 10 1, smlar to estuarne condtons Tracer Study Near unform mxng occurs between 8-15 mn.

8 Current State of Modelng Fracton of dspersed ol resurfacng s functon of vertcal dsperson rate and ol coalescence rates. Two methods for calculatng resuspended fracton Macay et al. (1980) Delvgne and Sweeney (1988) Both methods emprcally based Sngle value for dsperson coeffcent Determned through dye-tracer experments Determned usng nomograms Ether method does not allow for spatal-temporal varablty Taylor (191), Batchelor (1950), Ippen (1966), Fsher, Lst et al. (1979), Tchobanoglous & Shcroeder (1985)

9 Shear Augmented Dffuson Where shear currents are present, shear dffusvty wll domnate over turbulent dffusvty Taylor's (1953 and 1954) Enhanced dffuson encountered even n lamnar flow Extenson of ths fndng to natural systems s subject of ongong research In a shallow wnd-drven bay, the velocty gradents that produce shear wll be more pronounced n the vertcal than n the lateral (horzontal) plane, except near the shore or close to land boundares)

10 Modelng Framewor Grayed out modules not mplemented n ths scheme Hydrodynamc Model Hydrodynamc Data HF Radar Model Coeffcents Velocty Dsperson Knetcs Transport Model 3-D Nowcastng Sngle PDE Data Vsualzaton 3-D wth GIS underlay Model Valdaton Tracer experments Data Assmlaton Computatonal Steerng Habtat Indcators Real-tme Data from montorng statons Model Calbraton

11 Model Descrpton Rate of change of concentraton measured by aggregate sum of gradent of advectve flux and gradent of dspersve flux and netcs C (uc ) (vc ) (wc ) C C C = + Dx + Dy Dz ± r t x y z x x y y + z z ) Rate of change of concentraton wth tme = Gradent of + Gradent of + Advectve flux Dspersve flux Transport Model coeffcents Velocty, dsperson, coalescence Soluton provdes concentraton profle C of the th component Source/ Sn Knetcs

12 Computatonal Grd and Bathymetry

13 Bacground Theory - Dffuson K K T = u = u t = 0 Turbulent Dffuson t ' 0 ' T R ( τ ) dτ ' ' u ( t) u ( t+ τ) R ( τ) = u( t) R ( τ ) dτ ' (Integral tme scale of turbulence) (Lagrangan autocorrelaton Functon) Shear Dffuson K I xe = h u ' K xe = u Tc. I T = h ' c K z K 1 z z = " 1 u ' K 0 0 z 0 ' z I ' " ' ' ' u dz dz dz Depends on tme to complete vertcal mxng (quassteady state) or ntalzaton tme, Tn Proportonal to characterstc tme scale, Tc Tn = ϑ.tc Typcal values of ϑ 1.0 (Chatwn, 197) 0.4 (Fscher, 1968) 1/π or 0.1 (Oubo and Carter) ϑ = 1 equvalent to usng full depth for the mxng length

14 Bacground Theory - Coalescence Advecton Dsperson Reacton Equaton C = Dz t Upper Boundary v s, C t = ( ρ ρ ) = r D ol z z = = Coalescence f = 0 surf water w + j= C z w C z + r ( Partally Absorbtve) w C Bottom Boundary(Reflectve) D Surfacng Velocty ( Stoes Equaton) 1 μ d Knetcs αβ g ( υ, υ j ) nn j αβ ( υ, υ ) = 1 n n

15 Evaluaton of Turbulent Dffusvty Usng computed values of T L Equaton (5) s appled n dscretzed form to the tmeseres Current averagng s performed usng a sldng wndow Equvalent to applyng a low-pass flter Flter sze determned wth the ad of spectral analyss on tme-seres of velocty K s the product of mean square velocty <u > and T L Computed over the same tme nterval as R

16 Evaluaton of Shear Dffusvty Determne T c usng K z from turbulent dffusvty calculatons (Eq. 17) Obtan vertcally averaged square velocty <u > Obtan characterstc ntegral, I usng dscretzed form of Eq. 16 Values of I falls wthn range recommended (Fscher, 1973); K s product of all three quanttes evaluated over tme Generates tme-seres of K values

17 Evaluaton of Droplet Coalescence Knetcs Collson Frequency (β) Depends on Hydrodynamc Energy Energy characterzed usng scalng parameter, G m (mean velocty gradent) Modeled as the sum of collson frequences due to the Brownan (β Br ), shear (β Sh ), and dfferental sedmentaton (β ds ) mechansms (Ernest et al., 1995) β( ν,ν j ) and β(ν,ν ) are the collson frequences between droplets wth volumes of ν and ν j and ν and ν Collson Effcency (α) Depends on droplet nteracton forces Repulson force nfluenced by Salnty fracton of collsons that result n droplet coalescence Based on chemstry; emprcally determned n,j, : partcle number concentraton n a sze nterval,j are subscrpts desgnatng droplet sze class r = 1 + j = αβ ( υ ), υ j n n j αβ ( υ, υ ) = 1 n n

18 Dspersed ol n batch reactor All data 30 0 /00, 40s -1 Predcted α = 0.89 Tme ( sec) 30 0/00, 40 s-1 Observed Concentratons (ul/l) 6.00E E-0 y = 0.99x R = E E-0.00E E E E E-0.00E E E E E-0 Predcted Concentratons (ul/l)

19 Droplet Dstrbuton Observed Predcted 6.00E E E E-0 Concentraton (ul/l) 4.00E E-0.00E-0 0 sec 900 sec 1800 sec 700 sec 3600 sec Concentraton (ul/l) 4.00E E-0.00E-0 0 sec 900 sec 1800 sec 700 sec 3600 sec 1.00E E E Droplet Dameter (um) 0.00E Droplet Dameter (um)

20 Dspersed Ol Dstrbuton: 30 0 /00, 30 s Concentraton (ul/l) Tme (mn) (Smulated) Expermental

21 Dspersed Ol Dstrbuton: 10 0 /00, 30 s Concentraton (ul/l) Tme (mn) Expermental (Non-nteractng)

22 Turbulent Dffusvty vs. Depth Depth (cm) Study 088_ 50 Dff. x Dff. y Dff. z Dffusvty (cm /s) Study 088_1 Depth (cm) Dff. x Dff. y Dff. z Dffusvty (cm /s) 300 Study Depth (cm) Dff. x Dff. y Dff. z Dffusvty (cm /s)

23 Spatal Dstrbuton of Dffusvty x x Lattude Lattude Longtude Longtude 0 Dffusvty Values from Hydrodynamc Observatons Generates spatally dstrbuted and temporally varyng values for dsperson when modelng a water body. Uses data from HF radar and acoustc Doppler current proflers (ADCP). Ths concept replaces the use of sngle value to represent dsperson when modelng a water body.

24 Dye Patch Characterstcs Computed vs. Observed Spread Aspect rato?? 7.80 Conc (ppb) Lattude Longtude 0

25 Comparson of Varance Estmates Varance (cm ) Tme (s) Study 088_ Study 1007 Murthy 1 Murthy Ellot Oubo Fcan

26 Model Error Analyss Normalzed Error Normalzed Error Cell Reynolds Number, R e Cell Reynolds Number, R e

27 Evoluton of Contamnant Plume From Model Smulaton

28 On-gong Modelng Studes conducted Hydrodynamc scalng Transport -D 3-D Estmaton of dsperson coeffcents Shear studes Dye experments Consttuent transport Water qualty parameters Dspersed ol Model development v