ISSN:
0271-2091
Keywords:
Finite difference
;
Unsteady flow
;
Spatially periodic flows
;
Engineering
;
Engineering General
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
A numerical study is made of the unsteady two-dimensional laminar flow of an incompressible fluid over a periodically grooved wall. Two independent finite difference techniques are employed. One is based on the vorticity-stream function and the other on the vorticity-velocity (i.e. induction law) formulation. The fluid motion is initiated impulsively from rest and is assumed to be spatially periodic in the streamwise direction. The numerical formulations are derived in detail. The generation of vorticity at the solid surface is modelled differently in the two approaches, and this is found to play an important role in determining the surface pressure distribution and the drag coefficient. The flow field is examined during the early transient phase of development, during which the greatest changes occur. Results are presented for a moderate Reynolds number (based on groove depth) equal to 100. It is found that the vorticity-stream function approach does not produce a spatially periodic wall pressure distribution, and therefore global conservation of total vorticity is not achieved. This results in substantial errors in the predictions for the drag coefficient. These deficiencies are not found in the results obtained by the vorticity-velocity formulation.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/fld.1650081104
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