Numerical Method for Determining Three-Dimensional Response of a Wing to Incident Turbulence

摘要

A method is developed to numerically determine the response of three-dimensional wings to turbulent upwash. The method uses a generalized gust response function in the place of the Sears function that differentiates the strip experiencing the gust and the strip producing force. This generalized gust response function is computed with an unsteady vortex lattice method. The vortex lattice operates in the time domain to simulate the development and relaxation of the wake to steady state and then switches to a frequency domain approach to evaluate the gust response. The total wing response to homogenous isotropic turbulent inflows is numerically integrated to produce stochastic turbulent lift spectra. The numerically generated transfer functions are compared to the Sears and Filotas gust response functions. The effect of finite span and sweep on both the transfer functions and lift spectra are investigated.