• The Journal of the Acoustical Society of Korea
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• v.13 no.2
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• pp.23-29
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• 1994

In this paper, the measured in-water radiation impedance of cylindrical piezoelectric radiator with finite baffle is compared to the existing theoretical result of that with infinite baffle and the effect of baffle on the radiation impedance is examined. Comparision between measurement and theoretical result of radiation impedance shows that the measured radiation impedance tends to be that of the infinite baffle as the baffle length increases. Another finding of the comparision in that the effect of baffle is more dominant in radiation reactance than in radiation resistance. Therefore, for the use of theoretical radiation impedance of infinite baffle on the design of acoustic transducer, the impedance compensation to the baffle length should conducted.

• The Journal of the Acoustical Society of Korea
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• v.14 no.4
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• pp.82-88
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• 1995

Conductance and susceptance of the self-radiation impedance in a rectangular acoustic sensor without baffle are measured experimentally. Finite polyurethane window is mounted at the end of the acoustic sensor. The sensor radiation impedance is cauculated using the equivalent electric circuit. Using the Levine's integral equations of a rectangular piston mounted to the rigid infinite baffle, radiation resistance and reactance were simulated numerically. Numerical and experimental results are compared to each other.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.2
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• pp.32-39
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• 2005

The effectiveness of the pogo suppression device (PSD) on the response of the piping system simulating the fuel (or oxidizer) supply lines of the rocket engines was investigated. The system response defined as the ratio of the flow rate to the pressure in the main tube was obtained for various PSD gas volumes $((0\~2)\times10^{-3}m^3)$ and three different baffle hole diameters (5, 50, 115mm). Existence of a gas volume in the PSD reduced the system resonance frequency. With a larger gas volume, the resonance frequency became lower, but only slightly, while the fluctuations of the main tube pressure and the flow rate damped down considerably. The resonance frequency decreased with the increase of the PSD inlet restriction (or the decrease of the baffle hole diameter), though slightly. However, with a larger inlet restriction, the PSD pressure wave showed a delayed response with the smaller amplitude compared to the pressure variation in the main tube.

• Journal of Power System Engineering
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• v.13 no.2
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• pp.36-41
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• 2009

An experimental investigation was conducted to examine the fluid flow resistance in the rectangular channel with two inclined wire screen baffles. Two different types of wire screens; dutch weave and plain weave, were used as baffle devices in this experiment. Three kinds of baffles with different mesh specifications were made up of dutch type and four different kinds of baffles were made up of plain weave type. The stainless steel wire screen baffles were mounted on the bottom wall with varied angle inclination. Reynolds numbers were varied from 23,000 to 57,000. Results show that the mesh number of baffles plays an important role on friction factor behaviour. It is found that the baffle with the most number of meshes (type SA) has the highest fluid flow resistance.

• The Journal of the Acoustical Society of Korea
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• v.14 no.5
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• pp.58-62
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• 1995

Integral equations of self-radiation impedance of a rectangular piston in a rigid infinite baffle are derived using by polar coordinate. The self-radiation impedance is separated by two parts ; self-radiation resistance and self-radiation reactance. Derived integral equations are simulated by numerical method. Based on the numerical results, self-radiation impedance can be obtained in the low and high frequency ranges without any limited conditions.

• The Journal of the Acoustical Society of Korea
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• v.14 no.6
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• pp.21-26
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• 1995

In this paper integral equations are derived and simulated numerically for the mutual radiation impedance of an acoustic transducer in a Plane array. It is assumed that the pistons are mounted in the rigid infinite baffle. The mutual radiation impedance is separated into resistance and reactance and plotted as a function of ka and kd. Mutual radiation resistance is decreased and perturbed according to increase of ka. Mutual radiation reactance is decreased along to increase of ka. Mutual impedance is decreased when kd is increased. However, when ka is 6, 13, and 19 the interaction effect is decayed. When the relative piston position of the two pistons is 45 degree, the amount of interaction becomes minimized.