Cavity shedding of cavitating flows around an axisymmetric body belongs to the unsteady cavitating flows in the condition of steady incoming current.The periodic characteristics of unsteady cavitating flows around an ...Cavity shedding of cavitating flows around an axisymmetric body belongs to the unsteady cavitating flows in the condition of steady incoming current.The periodic characteristics of unsteady cavitating flows around an axisymmetric body at small angles of attack are investigated experimentally and numerically.The evolution and shedding process of the three-dimensional sheet cavitation are computed numerically by the Reynolds averaged Navier-Stokes equations and the RNG k-？model.The modification approach for eddy viscosity coefficient in the transition area of the two-phase flow is adopted to reproduce the shedding process of cavitating flows.The computed frequency of the cavity shedding coincides with the experimental data for the cases of unsteady cavitating flows around axisymmetric bodies with four headforms.Given the cavitation number,the shedding process of the cavitating flow depends heavily on the headform of the axisymmetric body.If the angle of attack of the axisymmetric body is greater than a critical value,the violent shedding of the sheet cavitation seems to be depressed.展开更多
An experimental investigation was conducted to study the cavitation inception of six isolated irregularities for negative and positive pressure gradients.The relationship between the root-mean-square of pressure fluct...An experimental investigation was conducted to study the cavitation inception of six isolated irregularities for negative and positive pressure gradients.The relationship between the root-mean-square of pressure fluctuation and the oscillating radius of gas bubble was determined in this paper.The results of the experiment show that the incipi- ent cavitation numbers for the same protrusions are higher and the intensities of pressure fluctuation are lower in negative gradient flows than that in positive pressure gradient flows.The peaks of pressure fluctuation are seven to twelve times that of the root-mean-square values of pressure fluctuation.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.10972138,11632012)the National Key Basic Research Development Program of China(973 Program,Grant No.2013CB036102)
文摘Cavity shedding of cavitating flows around an axisymmetric body belongs to the unsteady cavitating flows in the condition of steady incoming current.The periodic characteristics of unsteady cavitating flows around an axisymmetric body at small angles of attack are investigated experimentally and numerically.The evolution and shedding process of the three-dimensional sheet cavitation are computed numerically by the Reynolds averaged Navier-Stokes equations and the RNG k-？model.The modification approach for eddy viscosity coefficient in the transition area of the two-phase flow is adopted to reproduce the shedding process of cavitating flows.The computed frequency of the cavity shedding coincides with the experimental data for the cases of unsteady cavitating flows around axisymmetric bodies with four headforms.Given the cavitation number,the shedding process of the cavitating flow depends heavily on the headform of the axisymmetric body.If the angle of attack of the axisymmetric body is greater than a critical value,the violent shedding of the sheet cavitation seems to be depressed.
文摘An experimental investigation was conducted to study the cavitation inception of six isolated irregularities for negative and positive pressure gradients.The relationship between the root-mean-square of pressure fluctuation and the oscillating radius of gas bubble was determined in this paper.The results of the experiment show that the incipi- ent cavitation numbers for the same protrusions are higher and the intensities of pressure fluctuation are lower in negative gradient flows than that in positive pressure gradient flows.The peaks of pressure fluctuation are seven to twelve times that of the root-mean-square values of pressure fluctuation.
