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중첩 격자 기법이 적용된 대각 내재적 조화균형법을 이용한 헬리콥터 로터 블레이드의 비정상 공력 해석
임동균(D. K. Im),최성임(S. I. Choi),박수형(S. H. Park),김유진(E. Kim),권장혁(J. H. Kwon) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.11
In this paper, diagonal implicit harmonic balance method with overset grid technique is applied to analyze helicopter rotor blade flow in hover and forward flight condition. The chimera grid need interpolation time with sub-grid and background grid in moving problem such as forward flight on every time step. Present method is available enough to reduce the grid module interpolation time. In order to demonstrate present method, Caradonna & Tungs rotor blades are used and the results are compared to other researchers result and experimental data.
대각 내재적 조화균형법을 이용한 헬리콥터 로터 블레이드의 비정상 공력 해석
임동균(D. K. Im),최성임(S. I. Choi),박수형(S. H. Park),권장혁(J. H. Kwon) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.5
In this paper, diagonal implicit harmonic balance method is applied to analyze helicopter rotor blade flow. Periodic boundary condition for Fourier coefficients is also applied in hover and forward flight condition. It is available enough to simulate the forward flight problem with only one rotor blade using the periodic boundary condition in frequency domain. In order to demonstrate present method, Caradonna & Tung’s rotor blades are used and the results are compared to time-accurate method and experimental data.
임동균(D.K. Im),박수형(S.H. Park),권장혁(J.H. Kwon) 한국전산유체공학회 2010 한국전산유체공학회지 Vol.15 No.4
In order to analyze the periodic unsteady flow problem efficiently the partially implicit harmonic balance (PIHS) method was developed. Contrary to the existing harmonic balance method, this method handles the harmonic source term explicitly and deals with flux terms implicitly. This method has a good convergence in comparison with the full explicit harmonic method and it is easy to apply this method because there is no need to calculate the complicated flux Jacobian term by comparing with the full implicit harmonic method. With the multigrid method about the each harmonic it turns out that this method has a good convergence regardless of the number of harmonics. The oscillating flows over NACA0012 airfoil is considered to verify this method then the result correponsed to both the result of dual time stepping and explicit Runge-Kutfa method.
다중 격자 기법이 적용된 부분 내재적 조화 균형법을 이용한 비정상 유동 해석
임동균(D. K. Im),박수형(S. H. Park),권장혁(J. H. Kwon) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.11
In order to analyze the periodic unsteady flow problem efficiently the partially implicit harmonic balance(PIHB) method was developed. Contrary to the existing harmonic balance method, this method handles the harmonic source term explicitly and deals with flux terms implicitly. This method has a good convergence in comparison with the full explicit harmonic method and it is easy to apply this method because there is no need to calculate the complicated flux Jacobian term by comparing with the full implicit harmonic method. With the multigrid method about the each harmonic it turns out that this method has a good convergence regardless method. With the multigrid method about the each harmonic it turns out that this method has a good convergence regardless of the number of harmonics. The oscillating flows over NACA0012 airfoil is considered to verivy this method then the result correponsed to both the result of dual time stepping and explicit Runge-Kutta method.
대각 내재적 조화균형법을 이용한 헬리콥터 로터 블레이드의 비정상 공력 해석
임동균(D.K. Im),최성임(S.I. Choi),박수형(S.H. Park),권장혁(J.H. Kwon) 한국전산유체공학회 2011 한국전산유체공학회지 Vol.16 No.4
In this paper, the diagonal implicit harmonic balance method is applied to analyze helicopter rotor blade flow. The periodic boundary condition for Fourier coefficients is also applied in hover and forward flight conditions. It is available enough to simulate the forward flight problem with only one rotor blade using the periodic boundary condition in the frequency domain. In order to demonstrate the present method, Caradonna & Tungs rotor blades were used and the results were compared to the time-accurate method and experimental data.
중첩 격자 기법이 적용된 대각 내재적 조화균형법을 이용한 헬리콥터 로터 블레이드의 비정상 공력 해석
임동균(D. K. Im),최성임(S. I. Choi),김유진(E. Kim),권장혁(J. H. Kwon),박수형(S. H. Park) 한국전산유체공학회 2012 한국전산유체공학회지 Vol.17 No.1
In this paper, diagonal implicit harmonic balance method with overset grid technique is applied to analyze helicopter rotor blade flow in hover and forward flight condition. The chimera grid need interpolation time with sub-grid and background grid in moving problem such as forward flight on every time step. Present method is available enough to reduce the grid module interpolation time. In order to demonstrate present method, Caradonna & Tungs and AH-1G rotor blades are used and the results are compared to other researchers’ result and experimental data.
다중 투과면을 이용한 UH-1H 로터 블레이드의 제자리 비행 시 원방 소음 해석 연구
김기로(K.R. Kim),박수형(S.H. Park),박민준(M.J. Park),이덕주(D.J. Lee),박남은(N.E. Park),임동균(D.K. Im) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.3
In this study, aero-acoustics in far-field is computed for the UH-1H rotor blade in hovering flight. A Chimera grid method is applied in this simulation to consider the blade motion and moving effects. Multi-permeable surfaces surrounding a blade are constructed to include the flow noise generated from the shock wave and the tip vortices. A computation is performed with three-dimensional Euler’s equations. An acoustic analogy code using the Kirchhoff approach to Ffowcs Williams and Hawkings equations is applied to efficient the noise prediction caused by volume noise sources in far-field. The high speed impulsive noise on the rotor blade is predicted and validated according to the permeable surface locations. It is confirmed that the noise source caused by the shock waves generated on the blade surface is a dominant factor in the far-field noise prediction.