Waste impoundments are usually not protected by any growing crops, soil roughness, or wind barriers, and dust due to wind erosion of the surface waste material can be a major environmental problem. The tailings dam in...Waste impoundments are usually not protected by any growing crops, soil roughness, or wind barriers, and dust due to wind erosion of the surface waste material can be a major environmental problem. The tailings dam in Aitik is highly susceptible to wind erosion when it is dry and windy. Strong dust storms may occur during dry seasons. These events are short-lived but may transport a huge amount of particulate matter and adversely impact air quality in downwind areas. This study estimated material loss from the Aitik tailings dam using SWEEP model. The simulated total material loss, saltation and creep loss, suspension loss and PM10 loss were 4.4941 kg/m2, 0.042 kg/m2, 4.4559 kg/m2, 0.264057 kg/m2 respectively. To control the dust generation, wind breaks could be suggested to be installed at 800 m downwind the west side edge of the tailings dam to reduce the saltation and creep and it would in turn reduce suspended emission. The measured total suspended material for five days by exposure profiling method was 0.475 kg/m2, which had a big difference with a simulate value of 4.4559 kg/m2. Many reasons contributed to the disagreement of simulated value and measured value in this study. In order to use the model for mining industry, more tests are needed to validate the modeling result, and calibration methods could be useful in adjusting the internal coefficients and empirical equations.展开更多
The steady flow field of a canard missile on different angles of attack and Mach numbers were studied. Based on analysis, a method was proposed to reduce the calculation for the rolling characteristics of the canard m...The steady flow field of a canard missile on different angles of attack and Mach numbers were studied. Based on analysis, a method was proposed to reduce the calculation for the rolling characteristics of the canard missile with free-spinning tails, and was tested to obtain the relations between rolling moment coefficient, Mach number, and angle of attack. All the computed rolling moment coefficients obtained from the proposed method greatly agreed with the experimental results of FD-06 wind tunnel in CAAA, which proved that the method can not only reduce the calculation cost but also keep precision in calculating the rolling characteristics of canard missiles.展开更多
To study the rolling control characteristics of a canard-controlled missile, a series of wind tunnel experiment is conducted. The experimental method, the structure features of wind tunnel model and the experimental r...To study the rolling control characteristics of a canard-controlled missile, a series of wind tunnel experiment is conducted. The experimental method, the structure features of wind tunnel model and the experimental results are introduced in this paper. The experimental data show that the canard is an inefficient rolling control device for canard-controlled missile with fixed tail fins; but for the free-spinning tail fin configuration, the canard can conduct rolling control of the missile, and even have higher controlling efficiency under larger canard deflection angle.展开更多
文摘Waste impoundments are usually not protected by any growing crops, soil roughness, or wind barriers, and dust due to wind erosion of the surface waste material can be a major environmental problem. The tailings dam in Aitik is highly susceptible to wind erosion when it is dry and windy. Strong dust storms may occur during dry seasons. These events are short-lived but may transport a huge amount of particulate matter and adversely impact air quality in downwind areas. This study estimated material loss from the Aitik tailings dam using SWEEP model. The simulated total material loss, saltation and creep loss, suspension loss and PM10 loss were 4.4941 kg/m2, 0.042 kg/m2, 4.4559 kg/m2, 0.264057 kg/m2 respectively. To control the dust generation, wind breaks could be suggested to be installed at 800 m downwind the west side edge of the tailings dam to reduce the saltation and creep and it would in turn reduce suspended emission. The measured total suspended material for five days by exposure profiling method was 0.475 kg/m2, which had a big difference with a simulate value of 4.4559 kg/m2. Many reasons contributed to the disagreement of simulated value and measured value in this study. In order to use the model for mining industry, more tests are needed to validate the modeling result, and calibration methods could be useful in adjusting the internal coefficients and empirical equations.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.HEUCFG201815)
文摘The steady flow field of a canard missile on different angles of attack and Mach numbers were studied. Based on analysis, a method was proposed to reduce the calculation for the rolling characteristics of the canard missile with free-spinning tails, and was tested to obtain the relations between rolling moment coefficient, Mach number, and angle of attack. All the computed rolling moment coefficients obtained from the proposed method greatly agreed with the experimental results of FD-06 wind tunnel in CAAA, which proved that the method can not only reduce the calculation cost but also keep precision in calculating the rolling characteristics of canard missiles.
文摘To study the rolling control characteristics of a canard-controlled missile, a series of wind tunnel experiment is conducted. The experimental method, the structure features of wind tunnel model and the experimental results are introduced in this paper. The experimental data show that the canard is an inefficient rolling control device for canard-controlled missile with fixed tail fins; but for the free-spinning tail fin configuration, the canard can conduct rolling control of the missile, and even have higher controlling efficiency under larger canard deflection angle.
