Abstract: Three-dimensional CFD technology is applied in an RADICL model by solving laminar Navier-Stokes equations and transportation equations. Mixing and reaction of flows, gas-dynamics fields and gains are studied at different jet intensity. It is found that the penetration depth plays an important role for special distribution of small signal gain macroscopically. Strong impinges between jets and unsteady structures are induced by over-penetration in mixing flow field.