Three-Dimensional Numerical Modeling of Initial Mixing of Thermal Discharges at Real-Life Configurations
Publication: Journal of Hydraulic Engineering
Volume 134, Issue 9
Abstract
A three-dimensional Reynolds-averaged Navier–Stokes computational fluid dynamics (CFD) model is developed for simulating initial mixing in the near field of thermal discharges at real-life geometrical configurations. The domain decomposition method with multilevel embedded overset grids is employed to handle the complexity of real-life diffusers as well as to efficiently account for the large disparity in length scales arising from the relative size of the ambient river reach and the typical diffuser diameter. An algebraic mixing length model with a Richardson-number correction for buoyancy effects is used for the turbulence closure. The governing equations are solved with a second-order-accurate, finite-volume, artificial compressibility method. The model is validated by applying it to simulate thermally stratified shear flows and negatively buoyant wall jet flows and the computed results are shown to be in good overall agreement with the experimental measurements. To demonstrate the potential of the numerical model as a powerful engineering simulation tool we apply it to simulate turbulent initial mixing of thermal discharges loaded from both single-port and multiport diffusers in a prismatic channel and a natural river. Comparisons of the CFD model results with those obtained by applying two widely used empirical mixing zone models show that the results are very similar in terms of both the rate of dilution and overall shape of the plumes. The CFD model further resolves the complex three-dimensional features of such flows, including the complex interplay of the ambient flow and thermal discharges as well as the interaction between each of discharges loaded from multiple ports, which are obviously not accessible by the simpler empirical models.
Get full access to this article
View all available purchase options and get full access to this article.
References
Abarbanel, H. D. I., Holm, D. D., Marsden, J. E., and Ratiu, T. (1984). “Richardson number criterion for the nonlinear stability of three-dimensional stratified flow.” Phys. Rev. Lett., 52, 2352–2355.
Addad, Y., Benhamadouche, S., and Laurence, D. (2004). “The negatively buoyant wall-jet: LES results.” Int. J. Heat Fluid Flow, 25, 795–808.
Advanced American Diving Service, Inc. (AADS). (2004). “Georgia Pacific Wauna Mill outfall—Diffuser flow testing.” Rep., Prepared for Georgia Pacific Corp., AADS Portland, Ore.
Blumberg, A. F., Ji, Z.-G., and Ziegler, C. K. (1996). “Modeling outfall plume behavior using far field circulation model.” J. Hydraul. Eng., 122, 610–616.
Craft, T. J., Gerasimov, A. V., Iacovides, H., Kidger, J. W., and Launder, B. E. (2004). “The negatively buoyant turbulent wall jet: Performance of alternative options in RANS modeling.” Int. J. Heat Fluid Flow, 25, 809–823.
Daviero, G. J., and Roberts, P. W. (2006). “Marine wastewater discharges from multiport diffusers. III: Stratified stationary water.” J. Hydraul. Eng., 132, 404–410.
Davis, L., Davis, A., and Frick, W. (2004). “Computational fluid dynamic application to diffuser mixing zone analysis—Case studies.” Proc., 3rd Int. Conf. on Marine Waste Water Discharges and Marine Environment, Catania, Italy.
Durbin, P. A., and Pettersson Reif, B. A. (2001). Statistical theory and modeling for turbulent flows, Wiley, New York.
Frick, W. E., Roberts, P. J. W., Davis, L. R., Keyes, J., Baumgartner, D. J., and George, K. P. (2003). Dilution models for effluent discharges, 4th Ed., U.S. Environmental Protection Agency, Washington, D.C.
Ge, L., and Sotiropoulos, F. (2005). “3D unsteady RANS modeling of complex hydraulic engineering flows. Part I: Numerical model.” J. Hydraul. Eng., 131, 800–808.
Ge, L., Lee, S., Sotiropoulos, F., and Sturm, T. W. (2005). “3D unsteady RANS modeling of complex hydraulic engineering flows. Part II: Model validation and flow physics.” J. Hydraul. Eng., 131, 809–820.
He, S., Xu, Z., and Jackson, J. D. (2002). “An experimental investigation of buoyancy-opposed wall jet flow.” Int. J. Heat Fluid Flow, 23, 487–496.
Huang, L. C., and Jain, S. C. (1980). “An analytical and experimental study of multiple plumes.” Final Rep. EPRI-CS-1547, Iowa Institute Of Hydraulic Research, Iowa City, Iowa.
Hwang, R. R., Chiang, T. P., and Yang, W. C. (1995). “Effect of ambient stratification on buoyant jets in cross flow.” J. Eng. Mech., 121, 865–872.
Jirka, G. H., Doneker, R. L., and Hinton, S. W. (1996). User’s manual for CORMIX: A hydrodynamic mixing zone model and decision support system for pollutant discharges into surface waters, DeFrees Hydraulics Laboratory, Cornell Univ., Ithaca, N.Y.
Mason, P. J. (1989). “Large-eddy simulation of the convective atmospheric boundary layer.” J. Atmos. Sci., 46, 1491–1516.
Méndez-Díaz, M. M., and Jirka, G. H. (1996). “Buoyant plumes from multiport diffuser discharges in deep coflowing water.” J. Hydraul. Eng., 122, 428–435.
Miles, J. W. (1961). “On the stability of heterogeneous shear flow.” J. Fluid Mech., 10, 496–508.
Nezu, I. and Nakayama, T., and (1998). “Mutual-interaction between bursts and boils very near the free-surface of open-channel flows.” Environmental hydraulics, J. H. W. Lee, A. W. Jayawardena, and Z. Y. Wang, eds., Balkema, Rotterdam, The Netherlands, 297–303.
Paik, J., Escauriaza, C., and Sotiropoulos, F. (2007). “On the bimodal dynamics of the turbulent horseshoe vortex system in a wing-body junction.” Phys. Fluids, 19, 045107.
Paik, J., Ge, L., and Sotiropoulos, F. (2004). “Toward the simulation of complex 3D shear flows using unsteady statistical turbulence models.” Int. J. Heat Fluid Flow, 25, 513–527.
Paik, J., and Sotiropoulos, F. (2005). “Coherent structure dynamics upstream of a long rectangular block at the side of a large aspect ratio channel.” Phys. Fluids, 17, 115104.
Paik, J., Sotiropoulos, F., and Sale, M. J. (2005). “Numerical simulation of swirling flow in a complex hydroturbine draft tube using unsteady statistical turbulence models.” J. Hydraul. Eng., 131, 441–456.
Papps, D. A., and Wood, I. R. (1997). “The effect of an intermittent flapping motion on the properties of merging plumes.” J. Hydraul. Res., 35, 455–472.
Roberts, P. J. W., Maile, K., and Daviero, G. (2001). “Mixing in stratified jets.” J. Hydraul. Eng., 127, 194–200.
Roberts, P. J. W., Snyder, W. H., and Baumgartner, D. J. (1989a). “Ocean outfalls. I. Submerged wastefield formation.” J. Hydraul. Eng., 115(1), 1–70.
Roberts, P. J. W., Snyder, W. H., and Baumgartner, D. J. (1989b). “Ocean outfalls. II. Spatial evolution of submerged wastefield.” J. Hydraul. Eng., 115(1), 26–48.
Roberts, P. J. W., Snyder, W. H., and Baumgartner, D. J. (1989c). “Ocean outfalls. III. Effect of diffuset design on submerged wastefield.” J. Hydraul. Eng., 115(1), 49–70.
Seo, I. W., Kim, H. S., Yu, D., and Kim, D. S. (2001). “Performance of tee diffusers in shallow water with crossflow.” J. Hydraul. Eng., 127, 53–61.
Shih, L. H., Koseff, J. R., Ivey, G. N., and Ferziger, J. H. (2005). “Parametrization of turbulent fluxes and scales using homogeneous sheared stably stratified turbulence simulations.” J. Fluid Mech., 525, 193–214.
Sotiropoulos, F., and Adballah, S. (1991). “The discrete continuity equation in primitive variable solutions of incompressible flow.” J. Comput. Phys., 95, 212–227.
Strang, E. J., and Fernando, H. J. S. (2001). “Entrainment and mixing in stratified shear flow.” J. Fluid Mech., 428, 349–386.
Tang, H. S. (2006). “Study on a grid interface algorithm for solutions of incompressible Navier–Stokes equations.” Comput. Fluids, 36, 1372–1383.
Tang, H. S., Jones, S. C., and Sotiropoulos, F. (2003). “An overset-grid method for 3D unsteady incompressible flows.” J. Comput. Phys., 191, 567–600.
Tian, X., and Roberts, P. J. W. (2003). “A 3D LIF system for turbulent buoyant jet flows.” Exp. Fluids, 35, 636–747.
Tian, X., Roberts, P. J. W., and Daviero, G. J. (2006). “Marine wastewater discharges from multiport diffusers. IV: Stratified flowing water.” J. Hydraul. Eng., 132, 411–419.
Viollet, P. L. (1980). “Turbulent mixing in a two layer stratified shear flow.” Proc., 2nd Int. Symp. on Stratified Flows, Trondheim, Norway, 315–325.
Yannopoulos, P. C., and Noutsopoulos, G. C. (2006a). “Interaction of vertical round turbulent buoyant jets—Part I: Entrainment restriction approach.” J. Hydraul. Res., 44, 218–232.
Yannopoulos, P. C., and Noutsopoulos, G. C. (2006b). “Interaction of vertical round turbulent buoyant jets—Part II: Superposition method.” J. Hydraul. Res., 44, 233–248.
Zhang, X.-Y., and Adams, E. E. (1999). “Predication of near field plume characteristics using far field circulation model.” J. Hydraul. Eng., 125, 233–241.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 134 • Issue 9 • September 2008
Pages: 1210 - 1224
Copyright
© 2008 ASCE.
History
Received: Jul 25, 2007
Accepted: Mar 18, 2008
Published online: Sep 1, 2008
Published in print: Sep 2008
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.