Abstract: In this paper a method of predicting the maximum distortion IDC and IDR of the the outlet flow field of the intake is presented. As in the instantaneous IDC, the minimum value of the total pressure distributed along a ring is involved; it is not so easy to predict the maximum distortion in a certain duration directly. To overcome this difficuly it is proposed to find the maximum IDC at a location within a duration with the assumption of normal distribution of APD of distortion at first and then to compare the IDC's of different locations obtained to find the maximum IDC of the whole flow field. The predicted maximum IDC and IDR are compared with experimental results with satisfaction. Meanwhile, the formulas for calculating the time average and R.M.S. values of IDC and IDR are derived.

Key words: instantaneous maximum distortion, IDC and IDR, prediction of maximum pressure distortion