• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.3
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• pp.182-188
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• 2016

This study investigates cavity flows through a guide grill above a resonator. Vortex distributions and intake flows are simulated for various shapes of the guide grill. The flows are assumed to be compressible, unsteady, and turbulent. Numerical simulations are conducted using a large eddy simulation (LES) model. To analyze the effect of the guide grill shape, three cavity lengths (0.2H, 0.6H, and 1.0H) and cavity angles ($30^{\circ}$, $45^{\circ}$ and $60^{\circ}$) are considered based on resonator height (H). The results show that the vortex generated in the resonator by cavity flow increases with cavity length. Thus, the intake flow is minimum at the smallest cavity length and angle. However, when cavity length is equal to resonator height, the intake flow decreases. The maximum intake flow occurs at a cavity angle $45^{\circ}$ at higher cavity lengths owing to the interaction between the vortex in the resonator and intake flow.

• Journal of Aerospace System Engineering
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• v.14 no.1
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• pp.8-15
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• 2020

In this paper, we propose a container wall and its boundary layer insulation design method that can maintain the temperature inside the spacecraft shipping container constantly under the condition that the heat or the external temperature changes severely to safely transport the satellite to the launch site. We will examine if the temperature inside the satellite shipping container is kept constant through the heat flow analysis and the satellite heat transfer analysis for the external environment of the satellite shipping container. Through the flow analysis inside the container, the flow distribution around the satellite in the container is analyzed, and the auxiliary fan, air conditioning system and special grill guide structure design for improving and optimizing heat flow performance are proposed.

• Journal of KSNVE
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• v.9 no.4
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• pp.730-737
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• 1999

This paper illustrates the sound vibration phenomenon of mono type TV set produced by spearker and suggests guidelines for reducing the noise induced by the sound vibrations. In order to illustrate the sound vibration phenomenon, the structural acoustic coupled analysis for the grill and cavity of speaker and structural analysis for main frame are performed. To veify the structural analysis results, experimental modal test is carried out. It is found that the acoustic excitation in the cavity is negligible and main sound vibrations occur near the bottom of TV set. An improved model is found by doing structural modifications based on structural analysis and sound vibration tests are performed to verify the validation of the improved model. The obtained results are applied to similar models and design guide lines for noise reduction are suggested.