Wind Tunnel Test Study On Wind-sand Flow Field And Wind-sand Resistance Of Buildings

Wind-sand two-phase flow was simulated by means of airflow carrying sand based on wind tunnel test to analyze the characteristics of the wind-sand flow field under different wind speed and falling sand amount.On the basis of studying the characteristics of wind-sand flow field,high-frequency dynamic force balance and PZT-5A piezoelectric ceramic plate force measuring elements were used to measure the average sand impact force on the windward face of buildings under the wind-sand flow field,and the variation law of sand impact force with different influencing factors was analyzed.The study shows that the characteristics of wind-sand two-phase flow are mainly related to the wind speed and the amount of falling sand.When the indicated wind speed and the amount of falling sand are kept constant,the sand concentration decreases with the increase of height because of its own gravity.The sand concentration at the measuring point at the same height increases with the increase of falling sand amount when the indicated wind speed remains unchanged.When the amount of falling sand remains unchanged,the sand concentration increases with the increase of the indicated wind speed in the region with a slightly higher height but decreases with the increase of the indicated wind speed in the region with a slightly lower height.Sand particles have a certain weakening effect on wind speed and a certain enhancing effect on turbulence,and the greater the sand concentration is,the more obvious the weakening and enhancing effect will be.Under the action of net wind field and wind-sand flow field,the effect of windsand flow field measured by balance on buildings is greater than that of net wind field.The calculation and analysis of the sand impact force show that the average sand impact force on the windward face of the building is related to the indicated wind speed,the amount of falling sand and the height: the force decreases with the increase of the height and increases with the increase of the sand concentration and wind speed.Under the action of net wind field and sand flow field,the average sand impact force measured by PZT-5A piezoelectric ceramic plate has the same rule as that measured by high-frequency dynamic balance,indicating that the piezoelectric ceramic plate is suitable for measuring the average sand impact force of buildings.However,the result measured by PZT-5A piezoelectric ceramic plate is larger than that by highfrequency dynamic balance.