Numerical simulation of gas-dynamic processes in a pipe open at one end

The problem of sudden opening of one end of a circular pipe containing a pressurized gas is considered. A new form of the boundary condition at the open end of the pipe is proposed that takes into account the local hydrodynamic drag due to the nonlinearity of the real physical problem. The system of gas-dynamic equations is integrated by the Godunov numerical method of discontinuity decay. The procedure of numerical realization of the nonlinear boundary condition at the open end of the pipe is described in detail. Comparison of the graphs obtained in the calculations with experimental data indicates that the proposed technique is appropriate.