Propeller slipstream effect uncertainty obtaining method based on random polynomial chaos expansion

The invention discloses a propeller slipstream effect uncertainty obtaining method based on random polynomial chaos expansion. The method comprises the following steps: firstly, carrying out statistics on each moment of an uncertainty variable in the flight process of the propeller-driven aircraft; constructing a basis of each order of polynomial, and performing Latin hypercube sampling on uncertainty variables in the flight data; system responses at the corresponding sampling points are obtained according to CFD simulation; calculating a polynomial coefficient through a least square method so as to obtain a polynomial function of system response; judging whether the highest order of the polynomial is sufficient or not and whether the goodness of fit of the chaotic polynomial to the system meets the requirement or not; taking a flight data acquisition point corresponding to the uncertainty variable as input to obtain a system random response surface; and finally, probability distribution of system response ca