@techreport{oai:jaxa.repo.nii.ac.jp:00045252,
 author = {白水, 正男 and SHIROUZU, Masao},
 month = {Aug},
 note = {The new operation method for shock tunnels which was proposed and verified experimentally by Soga et al.provides a much longer flow duration than that obtained by conventional operation methods. The new operation method employs an orifice plate between the driver and driven sections in order to modify the pressure history at the end of the driven section (i.e.stagnation condition for the nozzle flow) so that the pressure may stabilize much earlier than when an orifice plate is not used. In this new operation method, the first and the second diaphragms are replaced by high-speed valves. The second high-speed valve is kept closed until the pressure is stabilized. Although the effectiveness of the new method was verified experimentally, a technique for predicting the characteristics of facilities was necessary in order to choose the operation parameters for the Middle-Scale Shock Tunnel and to modify the tunnel. Numerical simulations of the flow in the shock tunnel under the new operation method were made emplying the PLM (Piecewise Linear Method). The flow was calculated two-dimensionally in the region near the orifice and one-dimensional flow was assumed in other regions. The simulated pressure history agreed well with the experimental results under various opening area ratios of the orifice. A method was proposed to reduce disturbance in the stagnation pressure caused by the rarefaction wave in the driver section and its effect was verified experimentally. As an example of the application of this simulation technique, the optimal opening ratio of the orifice for a pre-heated shock tunnel is provided. Modification of the NAL Gun Tunnel to change it to this type of tunnel is under way. Some guiding principles for the optimal design of a shock tunnel using the new operation method are given based on the present simulation., 資料番号: NALTR0993000, レポート番号: NAL TR-993},
 title = {A Numerical Simulation of a New Operation Method for Shock Tunnels},
 year = {1988}
}