Abstract
Linear and nonlinear inversion schemes to retrieve collision kernels of droplets in turbulent air flows from the time variation of droplet size distribution are developed. In order to validate the schemes, the collision kernels retrieved by the linear and nonlinear inversion schemes and those obtained by three-dimensional direct numerical simulations (DNS) are compared. The results show that the error of the retrieved collision kernels by the linear inversion scheme is about 24% for the low Reynolds number and increases up to 43% as the Reynolds number increases. On the other hand, the increase in the error of the nonlinear inversion scheme is suppressed, and the error is about 27% even for the high Reynolds number.
