A Comparison of Navier Stokes and Network Models To Predict Chemical Transport In Municipal Water Distribution Systems.

We investigate the accuracy of chemical transport in network models for small geometric configurations. Network model have successfully simulated the general operations of large water distribution systems. However, some of the simplifying assumptions associated with the implementation may cause inaccuracies if chemicals need to be carefully characterized at a high level of detail. In particular, we are interested in precise transport behavior so that inversion and control problems can be applied to water distribution networks. As an initial phase, Navier Stokes combined with a convection-diffusion formulation was used to characterize the mixing behavior at a pipe intersection in two dimensions. Our numerical models predict only on the order of 12-14 % of the chemical to be mixed with the other inlet pipe. Laboratory results show similar behavior and suggest that even if our numerical model is able to resolve turbulence, it may not improve the mixing behavior. This conclusion may not be appropriate however for other sets of operating conditions, and therefore we have started to develop a 3D implementation. Preliminary results for duct geometry are presented.

[1]  Samuel Scott Collis,et al.  The Local Variational Multiscale Method for Turbulence Simulation. , 2005 .

[2]  U. Piomelli,et al.  Wall-layer models for large-eddy simulations , 2008 .

[3]  M. Lesieur,et al.  New Trends in Large-Eddy Simulations of Turbulence , 1996 .

[4]  S. Scott Collis,et al.  Discontinuous Galerkin Methods for Turbulence Simulation , 2002 .

[5]  S. Scott Collis,et al.  Discontinuous Galerkin Methods for Compressible DNS , 2003 .

[6]  Samuel Scott Collis,et al.  The Local Variational Multiscale Method , 2005 .

[7]  Lorenz T. Biegler,et al.  Time Dependent Contamination Source Determination: A Network Subdomain Approach for Very Large Water Networks , 2004 .

[8]  Cynthia A. Phillips,et al.  Sensor Placement in Municipal Water Networks , 2003 .

[9]  J. N. Shadid,et al.  A Fully-coupled Newton-Krylov Solution Method for Parallel Unstructured Finite Element Fluid Flow, Heat and Mass Transfer Simulations , 1999 .

[10]  S. Collis,et al.  Monitoring unresolved scales in multiscale turbulence modeling , 2001 .

[11]  S. Scott Collis,et al.  The DG/VMS Method for Unified Turbulence Simulation , 2002 .

[12]  John N. Shadid,et al.  Efficient Parallel Computation of Unstructured Finite Element Reacting Flow Solutions , 1997, Parallel Comput..

[13]  T. Hughes,et al.  Large Eddy Simulation and the variational multiscale method , 2000 .

[14]  P. Moin,et al.  DIRECT NUMERICAL SIMULATION: A Tool in Turbulence Research , 1998 .

[15]  John N. Shadid,et al.  Analysis of gallium arsenide deposition in a horizontal chemical vapor deposition reactor using massively parallel computations , 1999 .

[16]  Lorenz T. Biegler,et al.  Contamination Source Determination for Water Networks , 2005 .

[17]  John N. Shadid,et al.  MP Salsa: a finite element computer program for reacting flow problems. Part 1--theoretical development , 1996 .