基于泥沙异重流稳定性与衰减过程的床面淤积特性研究OA北大核心CSTPCD

During the process of the stable stratification and continuous attenuation of sediment density current,it is accompanied by changes in the characteristics of sediment deposition on the bed.Based on the observed process of stable stratification and attenuation of density current in the flume experiment,and combining with the theoretical model of sediment density current movement the influence of the"stability-attenuation"process of density current on the bed deposition has been explored.Research results show that:with the increase of the density or thickness of lower density current,the formation time of stable stratification of density current is significantly shortened,and the maintenance time of stratification is prolonged.The theoretical results also show that the critical Reynolds Recr and the imaginary part of the disturbance wave num-ber αi increase under these conditions,which indicates that the stability of stratification is enhanced and the stabe movement of density current plays an important role in reducing bed deposition.In the experiment,the critical Reynolds number Recr increased by 568～820,the average deposition thickness decreased by 42％～46％.Therefore,improving the stability of density flow and delaying the deceleration rate can help improve the sediment transport rate and achieve the goal of reducing sediment deposition.