This paper numerically models the experimental results of Homae et al. in order to reveal the effect of a wall on a blast wave. The x, y, and z axes are defined as the direction between the origin and a midpoint of a wall, a horizontal direction vertical to the xaxis, and the height direction, respectively. Two cases of a wall, whose parameters are height H, width W and thickness T, are utilized. φwis determined as the azimuth angle of the corner of a wall. The peak overpressure with directional characteristics, which is caused by the reflection and diffraction of the blast wave at a wall, agrees well with the experimental results. The intensifying effect appears in the direction at right angles to φw. A triple point is generated by the reflection of the diffracted blast wave at the symmetric line (y=0), and propagates on the blast wave. Its path shows a unique profile in the plane of the scaled length y* in the y direction and similarity distance D*=(D-De-t)/De-t, where D and De-t denote distance between the explosion center and triple point in the x direction on the blast wave and distance between the explosion center and the origin of the triple point in the x direction.
numerical simulation, blast wave, wall, size effect, directional characteristics