The authors study a flow past a double cascade of solid profiles vibrating in a flow of an ideal incompressible liquid. Nonstationary vortex wakes modeled as contact discontinuities of the velocity past profiles are taken into account. Under the assumption that the amplitudes of vibrations are small, the problem is reduced to a system of two integral equations for the fluid velocity on the initial profiles of the double cascade. The authors derive formulas for computing the transient forces and moments. Finally, the authors study the influence of the form, mutual distance, and vibration laws of lattice profiles on these forces.