A pressure distribution measurement method for columnar shock waves in water

Abstract

The invention discloses a pressure intensity distribution measurement method capable of aiming at columnar shock wave in water. The columnar shock wave is two-dimensional shock wave; a photographic device is adopted to obtain a first image set when a light ray emitted from a light source passes through a two-dimensional water tank with speckle background and without the columnar shock wave; the photographic device is adopted to obtain a second image set when the light ray emitted from the light source passes through a two-dimensional water tank which has the speckle background and loads the columnar shock wave; on the basis of a first formula, through the comparison of the first image set and the second image set, determining the offset of the background speckle on the position of the columnar shock wave; on the basis of a second formula and a third formula, through the offset of the speckle, determining a light ray refractive index; and on the basis of a fourth formula and a fifth formula, through the light ray refractive index, determining the density and the pressure intensity of the columnar shock wave. By use of the method, shock wave spreading pressure intensity distributionin a small range can be obtained, and in addition, few pieces of optical equipment are used for achieving a purpose of observing shock wave spreading.

Description

technical field [0001] The invention relates to the field of pressure distribution measurement, in particular to a pressure distribution measurement method for columnar shock waves in water. Background technique [0002] The shock wave in water refers to the compression wave in which the pressure, density and temperature in the liquid medium change abruptly on the wave front. [0003] Due to the relatively low compressibility of water, the pulse width of shock waves in water is relatively narrow. At room temperature, the propagation speed of shock waves in water is greater than or equal to 1500mm / s. Therefore, measuring shock waves in water requires a high-frequency, high-resolution pressure sensor. For For single-point measurement of shock waves in water, PVDF (polyvinylidene fluoride) needle sensors, membrane hydrophones and optical fiber hydrophones are currently used more frequently. In the case of multi-point measurement or even for the measurement of shock wave pressur...

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Problems solved by technology

[0003] Due to the relatively low compressibility of water, the pulse width of shock waves in water is relatively narrow. At room temperature, the propagation speed of shock waves in water is greater than or equal to 1500mm / s. Therefore, measuring shock waves in water requires a high-frequency, high-resolution pressure sensor. For For single-point measurement of shock waves in water, PVDF (polyvinylidene fluoride) needle sensors, membrane hydrophones and optical fiber hydrophones are currently used more frequently. In the case of multi-point measurement or even for the measurement of shock wave pressure distribution, The traditional measurement method needs to use multiple pressure sensors. If it is in a relatively small space, it is difficult to arrange multiple pressure sensors.

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