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The noise generated in the rotary compressor can be classified by pressure pulsation of the refrigerant and structural vibration. This paper deals with the noise generated by pressure pulsation of refrigerant in a rotary compressor. During the operation of the compressor, the refrigerant and the internal structure of the compressor have strong interaction with each other. At this time, the oil around the reed valve causes the compressor to overpressure the refrigerant, which is the main cause of noise generation. Therefore, the interaction between the refrigerant and the valve during the compressor operation is analyzed using the FSI technique. The pressure pulsation of the refrigerant and the behavior of the valve were analyzed. Also, the noise characteristics were confirmed through the spectrum analysis of the generated noise.

During a lift-off of a launch vehicle, a large amount of acoustic wave is generated by jet plumes. Acoustic waves lead to pressure fluctuations on the surface of the vehicle in the form of acoustic loads and these are transmitted to the internal payload. In order to evaluate the effects of acoustic loads, we developed the integrated simulation model. The model is mainly divided into two parts, prediction and reduction parts. First, the external acoustic loads are predicted empirically based on the Distributing Source Method-II (DSM-II) of NASA SP-8072. We developed the improved method able to consider the additional effects of surrounding structures. We perform a next prediction process for the internal acoustic environment by using Statistical Energy Analysis (SEA). For the Korean Sounding Rocket-III (KSR-III), we predict the internal acoustic environment and evaluate the stability of the payload in the fairing. After the prediction process, we perform the noise reduction simulation. With an active noise control (ANC) simulation, we could confirm the possibility and reliability of the noise reduction system.

Empirical prediction method of the acoustic load on the fairing is based on jet experimental data on the basis of similarity principle. Representative empirical prediction method, DSM-II(Distributed Source Method-II), is a distributing source method along the jet plume. But the empirical prediction model is limited to reflect the impingement source in real environment because it is based on the free jet data. So, we propose a empirical prediction method considering the impinging jet effect by adding a impingement source in the existing prediction method. Considering the additional source's displacement, spectrum, strength and directivity, we calculate the acoustic load on the KSR-III(Korean Sounding Rocket-III) rocket and compare the results with the existing method and experiment data.

One of the main concerns of computational aeroacoustics is how to solve aeroacoustic problems with complex geometry. The dissipation/dispersion errors should be minimized to obtain accurate acoustic solutions because numerical solutions for aeroacoustic problems are over-susceptible. The wavenumber extended multi-dimensional interpolation techniques were developed in order to satisfy those requirements. The size of a stencil used for standard multi-dimensional interpolation can be determined. Adding the number of stencils with optimized interpolation coefficients enables obtaining the distribution function optimizing the relationship between dispersion and dissipation. Through the optimization process in frequency domains, this technique minimizes the dispersion/dissipation errors generated by the data transfer between multi-grid systems. In addition, a proper limiting process was proposed to remove a numerical instability and oscillations in a discontinuous region. Several problems were numerically simulated by applying the wavenumber extended multi-dimensional interpolation. The results of a advanced technique was validated by being compared with the existing conventional interpolation techniques.