抄録
The stretching term plays an important role in the three-dimensional flows; hence, it is necessary to examine in detail the numerical approach of this term in vortex methods. The present paper introduces the two approaches : (1) one is an ordinary vortex blod method and (2) another is based on the idea of the method of particle strength exchange. In the former approach, two mollified kernels are used, which are based on the Gaussian cut-off function and the algebraic cut-off function. The numerical example is a cluster of vortex rings flowed by the uniform velocity, which is the flow like a circular jet. The numerical results show that the approach (2) is fairly reasonable and the computational load of the approach (2) is lower than of the approach (1).
