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이덕주(Duck-Joo Lee),심인보(In-Bo Shim),허대녕(Dae-Nyoung Heo) 한국전산유체공학회 2000 한국전산유체공학회 학술대회논문집 Vol.2000 No.5
This paper presents a review of the methodology, problems and progress in computational aeroacoustics(CAA). The nature, characteristics, and objectives of aeroacoustics problems are quite different from the commonly encountered CFD problems. In this paper, computational methods that are designed especially for CAA applications are introduced. The potential offered by CAA, the numerical issues which need to be given careful attention, and some of the recent progress in solving aeroacoustic problem are discussed.
이덕주(Duck Joo Lee),김재욱(Jae Wook Kim),이인철(In Cheol Lee) 한국가시화정보학회 2004 한국가시화정보학회지 Vol.2 No.2
In this paper, computational aeroacoustics (CAA) method is used for flow-noise analysis and flow-noise visualization. High order high resolution scheme of optimized high order compact is used to resolve the small acoustic quantities and large flow quantities at the same time. An adaptive nonlinear artificial dissipation model and generalized characteristic boundary condition are also used. Aeolion tone noise, cavity noise, and jet noise are investigated. The visualizations of flow-noise are successful and characteristics of noise are studied. It is observed that the propagation directivity of noise is different with that of flow. With the help of CAA method, the visualization of noise is possible.
이덕주(Lee, Duck-Joo),김용석(Kim, Yong-Seok) 한국소음진동공학회 2007 한국소음진동공학회 논문집 Vol.17 No.1
Scattering fields of two dimensional acoustic waves by a circular cylinder are investigated. The present numerical approach for the acoustic scattering problem has difficulties of numerical robustness, long-time stability and suitability of far-field boundary treatments. The time-dependent periodic acoustic source is used to analyze Interference patterns between incident waves and waves reflected by the cylinder. Characteristic boundary algorithms coupled with 4th order Modified-Flux-Approach ENO(essentially non-oscillatory) schemes are employed in generalized coordinates to examine the effect of the wane frequency on the interference patterns. Non-reflecting boundary conditions, which is crustal for accurate computations of aeroacoustic problems, are used not to contaminate scattering fields by reflected waves at the outer boundary. Computed scattering fields show the circumferential acoustic modes generated by interacting between acoustic sources and scattered waves. At a lower frequency, the wave passes almost straight through the cylinder without Interacting with circular cylinder. Simulation results are presented and compared with the analytic solution. Computed RMS-pressure distribution on the cylinder wall is good agreement with exact solution.