Flow blockage and its effects on the loading of a model in the test section of a shock tube

To obtain a general survey of flow blockage and its effects on the loading of a model in the test section of a shock- and blast simulator for several blockage ratios with nondecaying shock waves, two-dimensional small-scale model tests with a simple model, namely a closed box-like structure, were made in the rectangular test section of a shock tube. Using shadowgraphs, pressure-time and impulse-time diagrams are taken at measuring points at the front, top, and rear of the model, and the processes are discussed. From these experiments it is concluded that at the present state of the investigations, simulations with blockage ratios greater than 0.1 cannot be recommended, except for special test situations and rough estimations.