DETERMINATION OF FLOWS PAST CURVED OBSTACLES WITH WAKES USING A MIXEDPROBLEM SOLUTION

Seeking improvements to the Helmholtz model, limited by its single wak e pressure, we consider a previously studied model and introduce virtu al walls in the flow field in order not to prescribe the wake pressure . As our treatment involves a symmetrical mixed problem with four disc ontinuities for the unit circle, we present a brief survey of the corr esponding mathematical theory. The numerical integration method used i s validated by computing analytical functions. A modified form of the Helmholtz model is proposed, keeping the original two-are mixed proble m. The solution found is favourably compared to the solution of a stan dard method. Coming back to the virtual wall model, the resolution met hod is described in detail, allowing the treatment of arbitrary symmet rical curved obstacles. As an innovation, the wake pressure is compute d without experimental data input. The model's predictive ability has been tested on some basic geometries (wedge, flat plate, elliptical an d circular cylinders). Clearly improving on results obtained by the He lmholtz model, this model gives drag and wake underpressure coefficien ts which often agree with experimental ones, the accordance being fair ly good for the circular cylinder in subcritical range.