Numerical Simulation And Wind Tunnel Test Of Flow Field Around Windbreak In Windy Sand Environment

At present,the construction and maintenance of China’s railway subgrade always face the erosion of wind and sand flow.Practice shows that the windbreak is an important engineering measure to ensure the smooth operation of the railway,which can effectively reduce the wind speed and hinder the damage to the line caused by wind and sand.By studying the law of the action of wind and sand flow on the roadbed and windbreak,it can guide the design and application of railway infrastructure.In this paper,the method of combining fluid numerical simulation and wind tunnel test is used to simulate the changes of the subgrade flow field of the two-phase flow of sand and sand after passing through different railway line types and windproof facilities,and analyze the speed distribution of wind sand on the railway embankment and windbreak wall.Impact,and to study the sand trajectory before and after the windbreak,the content of this paper is as follows:(1)Based on the basic theory of computational fluid mechanics,conduct research on different line types and windshields,derive the basic control of the fluid,and determine the parameters in the process of the numerical model of the sand flow.(2)Studying the movement characteristics of the flow field around the embankment under a single wind direction environment,it is concluded that as the height of the embankment increases,the flow field gradually becomes more complicated,and the low-speed area and the vortex range generated at the lee side slope foot are larger;When the slope of the embankment changes,the vertical velocity is more sensitive to the slope;by studying the different types of cutting patterns,it is concluded that the leeward side has the best shielding effect.(3)Study the influence of the height of the windbreak on the flat ground and embankment.Under different heights of the windbreak,the change law of the wind speed before the windbreak is the same and the height has little effect on it;the larger,the higher the windbreak,the better the shielding effect.(4)Study the velocity distribution law at the embankment,flat windbreak and embankment windbreak wall feature location,and obtain that under different initial wind speed environments,the wind speed changes within the shielding range of the embankment and the windbreak wall are small;later,the law of wind speed change is similar.(5)By studying the wind speed attenuation rate at the embankment characteristic position,the results show that the wind speed attenuation rate is less than 2m below the leeward side slope foot,and the windbreak wall accelerates the leeward side velocity,so in actual engineering,it should be Pay attention to the protection here.