采用基于剪切应力输运模型的改进延迟分离涡模拟(improvement of delay detached-eddy simulation,IDDES)方法对两串列圆锥柱体高雷诺数流动干扰问题进行了数值计算,分析了不同间距比对流场结构和受扰圆锥柱体气动力特性的影响。结果表...采用基于剪切应力输运模型的改进延迟分离涡模拟(improvement of delay detached-eddy simulation,IDDES)方法对两串列圆锥柱体高雷诺数流动干扰问题进行了数值计算,分析了不同间距比对流场结构和受扰圆锥柱体气动力特性的影响。结果表明:间距比对两串列圆锥柱体的流场特性影响明显;当间距比为2时,下游圆锥柱体受到上游圆锥柱体的遮挡影响,其平均阻力系数较低;当间距比为4时,上游圆锥柱体的尾涡在下游圆锥柱体表面发生再附,下游(受扰)圆锥柱体的脉动阻力系数比小间距比时有所增加;随着间距比的继续增加,当间距比为8时,上、下游圆锥柱体形成各自的旋涡脱落,下游圆锥柱体的脉动升力系数明显高于间距比为2~4时的情况。展开更多
主要研究纳米流体在压力梯度和外加电场作用下通过多孔管道的流动特性。首先,在Debye-Hückel近似下利用Poisson-Boltzmann方程求解电势场的分布。其次,利用物理相关的边界条件,求解动量方程得到纳米流体的速度的解析解。此外通过...主要研究纳米流体在压力梯度和外加电场作用下通过多孔管道的流动特性。首先,在Debye-Hückel近似下利用Poisson-Boltzmann方程求解电势场的分布。其次,利用物理相关的边界条件,求解动量方程得到纳米流体的速度的解析解。此外通过计算还得到了通道中纳米流体的流动电势和电动能量转换(Electrokinetic energy conversion,EKEC)效率的解析解。进一步用图像分析了流速、流动电势、EKEC效率和体积流率随偶应力参数、达西数、纳米颗粒体积分数和无量纲压力梯度参数变化的变化规律。展开更多
Due to the coexistence of compressibility,viscosity,and threedimensional effects,laminar flow is difficult to maintain for high-speed boundary layer on complex geometries.The unstable disturbance waves in the boundary...Due to the coexistence of compressibility,viscosity,and threedimensional effects,laminar flow is difficult to maintain for high-speed boundary layer on complex geometries.The unstable disturbance waves in the boundary layer are excited and rapidly increase during the receptivity process,so sufficiently large Reynolds stress causes the basic flow velocity profile to change,and the formation of turbulence is inevitable.展开更多
文摘采用基于剪切应力输运模型的改进延迟分离涡模拟(improvement of delay detached-eddy simulation,IDDES)方法对两串列圆锥柱体高雷诺数流动干扰问题进行了数值计算,分析了不同间距比对流场结构和受扰圆锥柱体气动力特性的影响。结果表明:间距比对两串列圆锥柱体的流场特性影响明显;当间距比为2时,下游圆锥柱体受到上游圆锥柱体的遮挡影响,其平均阻力系数较低;当间距比为4时,上游圆锥柱体的尾涡在下游圆锥柱体表面发生再附,下游(受扰)圆锥柱体的脉动阻力系数比小间距比时有所增加;随着间距比的继续增加,当间距比为8时,上、下游圆锥柱体形成各自的旋涡脱落,下游圆锥柱体的脉动升力系数明显高于间距比为2~4时的情况。
文摘主要研究纳米流体在压力梯度和外加电场作用下通过多孔管道的流动特性。首先,在Debye-Hückel近似下利用Poisson-Boltzmann方程求解电势场的分布。其次,利用物理相关的边界条件,求解动量方程得到纳米流体的速度的解析解。此外通过计算还得到了通道中纳米流体的流动电势和电动能量转换(Electrokinetic energy conversion,EKEC)效率的解析解。进一步用图像分析了流速、流动电势、EKEC效率和体积流率随偶应力参数、达西数、纳米颗粒体积分数和无量纲压力梯度参数变化的变化规律。
文摘Due to the coexistence of compressibility,viscosity,and threedimensional effects,laminar flow is difficult to maintain for high-speed boundary layer on complex geometries.The unstable disturbance waves in the boundary layer are excited and rapidly increase during the receptivity process,so sufficiently large Reynolds stress causes the basic flow velocity profile to change,and the formation of turbulence is inevitable.
