绕平头回转体初生空化的实验与数值研究

Experimental and numerical studies on inception cavitation around axisymmetric blunt body

综合应用实验与数值方法研究了绕平头回转体的初生空化。采用流动显示技术观察了绕平头回转体初生空穴的发展历程;数值计算采用一种RANS/LES的混合局部时均化湍流模型(PANS)。研究结果表明:初生空穴均发生在绕平头回转体的肩部分离旋涡区域,其形态呈和三维旋涡结构相关的纺锤状;伴随流场中旋涡运动,空穴自身也作着旋转运动且旋转轴即为纺锤状的长轴;绕平头回转体的初生空穴向下游运动的速度远小于主流速度。实验及数值结果均表明,从空化初生到溃灭的过程中,游离空穴随着主流向下游运动,在该研究中运动速度仅约为主流速度的10%-40%。

Inception cavitating flow around axisymmetric blunt body was studied based on the experiments and numerical simulations. A high-speed video camera was used to observe the process and structure of cavi- tation inception. A Partially-Averaged Navier-Stokes （PANS） method which was a hybrid RANS/LES tur- bulent model was applied in numerical simulations. The results show that the inception cavities which are spindle-like generate in the separate vortex of the blunt body. Beside moving along with changing vortexes in the field, inception cavities rotate themselves around their longer axes of spindle-like cavities. Inception cavities move downstream far less slowly than the inflow does. It is shown in both experimental and numeri- cal methods that during the whole developing process of travelling incept cavities, they move downstream by the velocities which are about 10% to 40% of mainstream velocity in this study.