用振荡射流抑制蓝藻滋长防止泥沙淤积

按照控制论的"反馈—放大—振荡"原理所构建的双稳态流体自控振荡器,可交替地从其两个输出孔断续地喷射出变向的水射束,从而促使周围水体激烈紊动,加强水中物质的交换能力.振荡射流扰动后,蓝藻能获得的光合能量将降低4倍.由于悬浮功Ws相对于自变量体积含沙量Sv的二阶导数为负值,高含沙浓度的泥浆流不但不会淤积反而会急剧冲刷河床.流控振荡器激扰促紊会导致分层流失稳,从而增大河流输沙能力.

Eliminating cyanobacteria growth by using oscillating water jets to prevent silt deposit

According to the principle of "feedback-amplifying-oscillating" in cybernetics,the bistable fluidic oscillator was constructed to issue alternate water jets through two exit ports,so as to promote turbulence intensity in water flow and enhance masstransfer ability.It is shown that the available photosynthetic energy of cyanobacteria is reduced by 4 times.The practice of Beijing cyanobacteria suppression programme has been recognizied as successful.Increase of turbulence intensity,induced by fluidic oscillator,would lead to instability of stratified flow,and enhance the silt-transporting capacity of the river flow.Owing to the curve of suspension work Ws with respect to volumetric content of silt Sv is concaved downward;silt-water mixed slurry,the heavenly laden flow might scour intensively instead of depositing as used to occur at Longmeng in the Yellow River,such an avalanche phenomenon being named as "excavating river bed" there.