Experimental Study On Physical Model Of Noise Generation Mechanism And Noise Reduction Measures Without Ridge Width

In recent years,many cities have built urban water landscape facilities in areas with relatively dense populations in order to improve urban landscape and optimize the living environment,such as broad-crested ridge-free weir.The urban water flow landscape facilities bring people visual enjoyment and also generate large water noise,which seriously affects the lives of residents in the communities surrounding water landscape facilities and endangers the mental health and physical.The mechanism of water noise is studied about the broad-crested ridge-free weir at different upstream flows,different downstream water depths and different height of weirs,based on dam project in the north of Miyi county,in order to reduce the harm caused by urban landscape water conservancy facilities.The water noise generated by the draining water flow and the water pressure generated by the toe are measured,and analyzes the relationship between the water noise and the water pressure.The result shows that both the noise value and the pressure value increase with the increase of the upstream flow and weir height,and decrease with the increase of the downstream water depth.Through the analysis of the experimental data,it is verified that the water noise is composed of two parts: one is the water noise generated by the impact of the lower downflow on the weir toe;the other is the water noise generated by the turbulence of the water flow itself.Reducing the water noise is to reduce the impact of the discharge water on the weir toe and the turbulence of the water flow itself.In order to further study the water noise treatment measures and find the noise reduction measures for the wide top weir without ridge,four different forms of gentle slopes are designed.The gentle slopes are the upward convex gentle slope,the linear gentle slope,the concave gentle slope and the stepped gentle slope.It is hoped that by constructing a gentle slope downstream of the broad-crested ridge-free weir to downfall height of the water flow,so as to reduce the impact of the downflow water on the toe and attenuate the turbulence of the water flow itself,thereby reducing the water noise.The experimental results show that the average noise reduction ability of linear gentle slope,upward convex gentle slope,concave gentle slope and stepped type gentle slope under different conditions are 18.14%,17.11%,16.75% and 0.65%,respectively.As the research on water noise of urban water landscape facilities is still in its infancy,and most of them have no specific engineering measures as reference.This paper understands the law of water noise generation,and also studies water noise treatment measures.The research results will provide theoretical support and technical measures for the noise reduction design of urban landscape dams,which is of great significance to the healthy development of urban water landscape facilities.