Theoretics Study of The Effect of Suction and Blowing on Turbulence

:Turbulence is very important in the equipment.It has direct relation to the performance and the power loss of the equipment. The turbulence in the equipment and the method for controlling wall-bounded flow should be studied.Turbulence is a very complicated flow state.Advances in the understanding of the coherent structure of wall-bounded turbulent flow have intensified interest in controlling near-wall turbulence.Many attempts have been made to devise a practical method for controlling wall-bound flows.These include the modification of the wall surface by installing riblets,as well as the use of a compliant wall or a spanwise oscillating wall.Among the approaches considered to date,the use of local suction and blowing deserves more detailed study because it provides an efficient and simple way for locally actuating the wall-bound flow.Moreover, the strength of the actuation can be controlled relative easy by local suction and blowing.Many engineering applications use local suction and blowing to modify a turbulent boundary layer. In this paper,the effects of localized periodic blowing on a turbulent boundary layer were investigated by numerical calculation.Periodic blowing with different frequency was applied through a spanwise slot by varying the velocity.It is concluded that, with a periodic blow-suction disturbance,the diversification of the velocity will be changed,the effect and the intensity of the turbulence can be decreased.According to this,the performance and the power loss of the equipment can be optimized.