A series of experiments on acoustic excitation on a multi-element airfoil performance were conducted in NF-3 wind tunnel in 2008. The results showed that internal acoustic excitation can change the aerodynamics characteristics of the airfoil under some conditions. This paper provides a computational method,which uses an assumption that turbulent kinetic energy can be a good analogy of acoustic excitation in study the effects of using internal acoustic excitation. Results of computation by solving 3D RANS are as follows:(1)The turbulent kinetic energy deduced lift in linear area of the airfoil by -2%(max) and improved lift around stall point by 5%(max);(2)The change on lift is smaller when the Reynolds number is higher;(3)When the O/L equals zero,the change on lift is the maximal one. These computational results are in good agreement with wind tunnel experiment in qualitative analysis. This paper confirms that the assumption of turbulent kinetic energy will be a nice expected approach to analogy of internal acoustic excitation.