Weak shock reflection from an open end of a tube with a baffle plate

Abstract

The present paper describes experimental and numerical investigations of a new boundary condition at an open end of a tube, in which a weak shock wave is discharged towards the surroundings. Experimental and computational investigations were performed on a simple shock tube with and without baffle plates. A numerical calculation was carried out for an unsteady, axisymmetric, inviscid, compressible flow. The size of baffle plate was varied in order to understand its effect on the reflection of the weak shock wave from the open end of the tube. With and without a baffle plate, the results of the experiment were in good agreement with those of numerical calculations. The results showed that an open end correction is subject to the presence of a baffle plate at the open end. An improved empirical equation for the reflection of the weak shock wave from the open end of a duct with and without a baffle plate was developed.

A new technique for the control of a weak shock discharged from a tube

“…1. According to previous work reported by K im et al [17,18], the size of the baf e plate, when it was less than 2.5 times the tube diameter, signi cantly affected the wave re ection phenomena occurring in the vicinity of the exit of the tube. In the present experiment, the baf e plate was large enough to ensure that it had no effect on the impulsive waves.…”

“…With regard to the discharge of a weak shock wave, more recently K im et al [17,18] carried out some experiments using an open-ended shock tube and computational works using the total variation diminishing (TVD ) scheme. The impulsive wave generated by the discharge of a weak shock was characterized in terms of the peak pressure, open-end correction, directional sensitivity and attenuation with the propagating distance [17,18].…”

“…The impulsive wave generated by the discharge of a weak shock was characterized in terms of the peak pressure, open-end correction, directional sensitivity and attenuation with the propagating distance [17,18]. It is, however, actually dif cult to assess a real noise level directly from an impulsive wave, because until now there has been no general rule for an assessment of impulsive noise.…”

Study of the Impulse Wave Discharged From the Exit of a Right-Angle Pipe Bend

“…A baffle plate of diameter of 4D is installed at the exit of the bends to be free from the pipe end effects which may occur at the exit of the bends [15,16]. The initial pressures of the shock tube are monitored by a personal computer system.…”

Computational study of an incident shock wave into a Helmholtz resonator

“…There are only a few works with regard to shock waves, in which, the Helmholtz resonator gas dynamics can be different from that of the sound waves. In case that a shock wave propagates into the Helmholtz resonator, the wave characteristics are influenced by very complicated shock wave dynamics, such as shock wave reflection and discharge [16][17][18][19][20][21][22], shock wave focusing [23,24], shock-vortex interaction [25], etc. At present, the associated wave phenomena are not known well.…”