TY - GEN
T1 - Assessment of turbulence modeling and wake-grid resolution for lift-offset coaxial rotor simulations
AU - Jia, Zhongqi
AU - Lee, Seongkyu
AU - Brentner, Kenneth S.
N1 - Funding Information:
This research was partially funded by the Government under Agreement No. W911W6-17-2-0003. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation thereon. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Aviation Development Directorate or the U.S Government. The authors would also like to thank: Dr. Roger Strawn from the U.S. Army Aviation Development Directorate (ADD) for providing the DoD High Performance Computing (HPC) resources and summer internship for the fist author; Mark Potsdam, Jain Rohit, Dr. Beatrice Roget, and Dr. Wel Chong (Ben) Sim from ADD for their beneficial advices and assistance on learning Helios; Neal Chanderjian and Williams Chan from NASA Ames for their technical advices on rotorcraft simulation and mesh generation.
Publisher Copyright:
© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
PY - 2018
Y1 - 2018
N2 - This paper examines the impact of wake-grid resolution and turbulence modeling on high-speed steady forward flight simulations of a modern lift-offset coaxial rotor XH-59A. The structured near-body grids are constructed using OVERGRID, and high-fidelity CFD/CSD loose coupling is achieved using the CREATE™-AV software Helios and rotorcraft comprehensive analysis code RCAS. Acoustic results are simulated based on high-fidelity CFD/CSD results and the acoustic software PSU-WOPWOP. The sensitivity of turbulence modeling and wake-grid resolution on nondimensional airloads and acoustics is studied based on four cases: SA-RANS with ∆finest= 10% CtipSA-DES with ∆finest= 10% CtipSA-DDES with ∆finest= 10% Ctipand SA-DES with ∆finest= 5% CtipNo significant discrepancy in airloads and acoustic predictions is shown between the different turbulence modeling cases at the forward flight speeds: 100, 150, and 200 knots. However, the SA-DES model with finest Cartesian spacing equal to 5% Ctippredicted slightly higher magnitude of airloads and acoustic pressure peaks than the same model with 10% Ctipspacing especially at high-speed. An increase of BVISPL up to 4 dB is detected with finer wake-grid spacing.
AB - This paper examines the impact of wake-grid resolution and turbulence modeling on high-speed steady forward flight simulations of a modern lift-offset coaxial rotor XH-59A. The structured near-body grids are constructed using OVERGRID, and high-fidelity CFD/CSD loose coupling is achieved using the CREATE™-AV software Helios and rotorcraft comprehensive analysis code RCAS. Acoustic results are simulated based on high-fidelity CFD/CSD results and the acoustic software PSU-WOPWOP. The sensitivity of turbulence modeling and wake-grid resolution on nondimensional airloads and acoustics is studied based on four cases: SA-RANS with ∆finest= 10% CtipSA-DES with ∆finest= 10% CtipSA-DDES with ∆finest= 10% Ctipand SA-DES with ∆finest= 5% CtipNo significant discrepancy in airloads and acoustic predictions is shown between the different turbulence modeling cases at the forward flight speeds: 100, 150, and 200 knots. However, the SA-DES model with finest Cartesian spacing equal to 5% Ctippredicted slightly higher magnitude of airloads and acoustic pressure peaks than the same model with 10% Ctipspacing especially at high-speed. An increase of BVISPL up to 4 dB is detected with finer wake-grid spacing.
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U2 - 10.2514/6.2018-4120
DO - 10.2514/6.2018-4120
M3 - Conference contribution
AN - SCOPUS:85051744416
SN - 9781624105593
T3 - 2018 Applied Aerodynamics Conference
BT - 2018 Applied Aerodynamics Conference
PB - American Institute of Aeronautics and Astronautics Inc, AIAA
T2 - 36th AIAA Applied Aerodynamics Conference, 2018
Y2 - 25 June 2018 through 29 June 2018
ER -