A hybrid numerical flux scheme is proposed by adapting the carbunclefree modified Harten-Lax-van Leer contact(HLLCM) scheme to smoothly revert to the Harten-Lax-van Leer contact(HLLC) scheme in regions of shear. This ...A hybrid numerical flux scheme is proposed by adapting the carbunclefree modified Harten-Lax-van Leer contact(HLLCM) scheme to smoothly revert to the Harten-Lax-van Leer contact(HLLC) scheme in regions of shear. This hybrid scheme, referred to as the HLLCT scheme, employs a novel, velocity-based shear sensor. In contrast to the non-local pressure-based shock sensors often used in carbuncle cures, the proposed shear sensor can be computed in a localized manner meaning that the HLLCT scheme can be easily introduced into existing codes without having to implement additional data structures. Through numerical experiments, it is shown that the HLLCT scheme is able to resolve shear layers accurately without succumbing to the shock instability.展开更多
Steady-state numerical simulations were conducted to capture the aerodynamic characteristics and flow patterns resulting from a tubercled and non-tubercled wing subjected to various combined pitch and yaw conditions a...Steady-state numerical simulations were conducted to capture the aerodynamic characteristics and flow patterns resulting from a tubercled and non-tubercled wing subjected to various combined pitch and yaw conditions at Re=1.8×10^(5).Pitch angle ranged from 0°to 25°,while two different yaw angles of 10°and 30°were used.Results show that 10°yaw angle does not impact upon the lift and drag characteristics significantly,while a 30°yaw angle leads to substantial lift and drag losses.Additionally,the tubercled wing continues to confer favourable stall-mitigating characteristics even for the larger yaw angle.Finally,despite skewing the flow structures significantly,the 30°yaw angle also reduces the formations of bi-periodic flow structures,flow separations and recirculating regions along the leading-edge tubercles,suggesting potentially better flow stability and controllability.展开更多
基金the Singapore Ministry of Education AcRF Tier-2 Grant(No.MOE2014-T2-1-002)the Graduate Research Officer Scholarship from School of Mechanical and Aerospace Engineering,Nanyang Technological University,Singapore。
文摘A hybrid numerical flux scheme is proposed by adapting the carbunclefree modified Harten-Lax-van Leer contact(HLLCM) scheme to smoothly revert to the Harten-Lax-van Leer contact(HLLC) scheme in regions of shear. This hybrid scheme, referred to as the HLLCT scheme, employs a novel, velocity-based shear sensor. In contrast to the non-local pressure-based shock sensors often used in carbuncle cures, the proposed shear sensor can be computed in a localized manner meaning that the HLLCT scheme can be easily introduced into existing codes without having to implement additional data structures. Through numerical experiments, it is shown that the HLLCT scheme is able to resolve shear layers accurately without succumbing to the shock instability.
基金the support for the research project by ETH ZurichNanyang Technological University, Singapore。
文摘Steady-state numerical simulations were conducted to capture the aerodynamic characteristics and flow patterns resulting from a tubercled and non-tubercled wing subjected to various combined pitch and yaw conditions at Re=1.8×10^(5).Pitch angle ranged from 0°to 25°,while two different yaw angles of 10°and 30°were used.Results show that 10°yaw angle does not impact upon the lift and drag characteristics significantly,while a 30°yaw angle leads to substantial lift and drag losses.Additionally,the tubercled wing continues to confer favourable stall-mitigating characteristics even for the larger yaw angle.Finally,despite skewing the flow structures significantly,the 30°yaw angle also reduces the formations of bi-periodic flow structures,flow separations and recirculating regions along the leading-edge tubercles,suggesting potentially better flow stability and controllability.
