Turbulent Flow Visualization in Computational and Experimental Hydraulics
Delft Hydraulics · 1995
Many practical problems in open channel hydraulics that were traditionally investigated in hydraulic model experiments, are nowadays being solved by using computational fluid dynamics. However, in order to interpret computational results, there is a clear preference among scientist and engineersfor visualization in analogy with experimental techniques. One such technique, particle tracing, enables a dynamic (Lagrangian) interpretation of a statically (Eulerian) computed vectorfield. However, quite often the emphasis in particle tracing is only on the mean flow properties, while effects due to dispersion and mixing ure often not accounted for. Hence turbulentjow characteristics have to be incorporated in a visualization system for practical hydraulic engineering problems. The particle tracing technique presented in this case study has been specifically developed to combine both mean andjuctuating velocity vectors, thus simulating stochastic perturbations around meanjow conditions. A number of cases are presented in this paper that demonstrate the practical applicabilityof advanced visualization techniques in realistic engineering studies. in this respect, and considerable advances have been made in the field of numerical flow modeling. However, in all applications of CFD, the huge amount of data generated by numerical flow simulations, are usually stored as a great number of discrete - and often time-dependent - data items like Eulerian velocity vectors and turbulent flow parameters on often extensivecomputational grids. Although calculations can be performed quite rapidly using present day computer technology, it does not help the researcher or the consulting engineer very much if he has to digest and interpret all this information from printouts or vector plots of computed numbers. Their interest is primarily directed towards understanding the physical implications of the numerical simulations.