Numerical method and optimization for contraction flow of water tunnel

Combining with low turbulence water tunnel, the flow field of 3D contraction segment with rectangular cross section was computed and analyzed. The finite volume method was used to solve unsteady Euler equation and the basic algorithm was the MacCormack time-dependent explicit predictor-correction method. For several typical contraction curves, the numerical computations of flow field were performed, and the wall pressure along the centerline or corner line at top or bottom and velocity distribution of exit segment were obtained, from which the optimal contraction curve meeting design requirement was chosen. It has been shown that the algorithm is valid for 3D contraction design.