In this paper, using the integration method, it is sought to solve the problem for the laminar boundary_layer on a flat plate. At first, a trial function of the velocity profile which satisfies the basical boundary co...In this paper, using the integration method, it is sought to solve the problem for the laminar boundary_layer on a flat plate. At first, a trial function of the velocity profile which satisfies the basical boundary conditions is selected. The coefficients in the trial function awaiting decision are decided by using some numerical results of the boundary_layer differential equations. It is similar to the method proposed by Peng Yichuan, but the former is simpler. According to the method proposed by Peng, when the awaiting decision coefficients of the trial function are decided, it is sought to solve a third power algebraic equation. On the other hand, in this paper, there is only need for solving a linear algebraic equation. Moreover, the accuracy of the results of this paper is higher than that of Peng.展开更多
Starting from the Simplified Navier-Stokes(SNS)equations presented at first by Godovachev-Kuzmin-Tsopov,and Gao Zhi,Davis,the authors analyze the character of the SNS equations for the laminarflow near the leading edg...Starting from the Simplified Navier-Stokes(SNS)equations presented at first by Godovachev-Kuzmin-Tsopov,and Gao Zhi,Davis,the authors analyze the character of the SNS equations for the laminarflow near the leading edge of a flat plate and far away from the plate by using the Weiner—Hopf meth-od and Fourier transform.It is proved that the solution of the SNS equations agree with the solution of the Navier-Stokes equations for flow near the leading edge of the plate and far away from the plate.How to match the solution of the SNS equations to the Blasius solution of the boundary layer equationsis also discussed.展开更多
采用直接模拟蒙特卡洛(direct simulation Monte Carlo,DSMC)方法对2个无限大平行平板之间的稀疏单原子气体一维热传导问题进行数值模拟,以探索不同稀薄程度条件下平板之间的气体压力、密度和温度的分布特征,获得导热系数随着温度的变...采用直接模拟蒙特卡洛(direct simulation Monte Carlo,DSMC)方法对2个无限大平行平板之间的稀疏单原子气体一维热传导问题进行数值模拟,以探索不同稀薄程度条件下平板之间的气体压力、密度和温度的分布特征,获得导热系数随着温度的变化关系。结果表明:传热建立稳态后平板之间的气体压力是均匀的,且与初始Knudsen数成反比,冷端(下方平板)附近的气体密度较大,Knudsen数较小,属于连续流动,热端(上方平板)附近的气体密度较小,Knudsen数较大,属于滑移流动。上下方平板附近均存在温度跳跃现象,初始Knudsen数越大,温度跳跃越明显,下方平板温度跳跃较小,上方平板温度跳跃较大。在所考虑的压力范围内,导热系数与气体压力无关,仅仅是气体温度的幂律函数,且导热系数的DSMC模拟结果与现有文献中的数据一致,验证了结果的可靠性。展开更多
文摘In this paper, using the integration method, it is sought to solve the problem for the laminar boundary_layer on a flat plate. At first, a trial function of the velocity profile which satisfies the basical boundary conditions is selected. The coefficients in the trial function awaiting decision are decided by using some numerical results of the boundary_layer differential equations. It is similar to the method proposed by Peng Yichuan, but the former is simpler. According to the method proposed by Peng, when the awaiting decision coefficients of the trial function are decided, it is sought to solve a third power algebraic equation. On the other hand, in this paper, there is only need for solving a linear algebraic equation. Moreover, the accuracy of the results of this paper is higher than that of Peng.
文摘Starting from the Simplified Navier-Stokes(SNS)equations presented at first by Godovachev-Kuzmin-Tsopov,and Gao Zhi,Davis,the authors analyze the character of the SNS equations for the laminarflow near the leading edge of a flat plate and far away from the plate by using the Weiner—Hopf meth-od and Fourier transform.It is proved that the solution of the SNS equations agree with the solution of the Navier-Stokes equations for flow near the leading edge of the plate and far away from the plate.How to match the solution of the SNS equations to the Blasius solution of the boundary layer equationsis also discussed.
文摘采用直接模拟蒙特卡洛(direct simulation Monte Carlo,DSMC)方法对2个无限大平行平板之间的稀疏单原子气体一维热传导问题进行数值模拟,以探索不同稀薄程度条件下平板之间的气体压力、密度和温度的分布特征,获得导热系数随着温度的变化关系。结果表明:传热建立稳态后平板之间的气体压力是均匀的,且与初始Knudsen数成反比,冷端(下方平板)附近的气体密度较大,Knudsen数较小,属于连续流动,热端(上方平板)附近的气体密度较小,Knudsen数较大,属于滑移流动。上下方平板附近均存在温度跳跃现象,初始Knudsen数越大,温度跳跃越明显,下方平板温度跳跃较小,上方平板温度跳跃较大。在所考虑的压力范围内,导热系数与气体压力无关,仅仅是气体温度的幂律函数,且导热系数的DSMC模拟结果与现有文献中的数据一致,验证了结果的可靠性。
