A numerical study on flow control of ship airwake during shipboard landing is carried out to address the effect of flow control devices on helicopter rotor airload. The in-house Reynolds Averaged Navier-Stokes(RANS) b...A numerical study on flow control of ship airwake during shipboard landing is carried out to address the effect of flow control devices on helicopter rotor airload. The in-house Reynolds Averaged Navier-Stokes(RANS) based solver Rotorcraft AeroDynamics and Aeroacoustics Solver(RADAS), with combination of momentum source approach is employed to conduct the helicopter shipboard landing simulation. The control effects of three aerodynamic modifications of ship superstructure, i.e. ramp, notch and flap, in different Wind-Over-Deck(WOD) conditions are discussed.From the steady simulation results, the effect of spatial variation of ship airwake on rotor airloads is concluded. The aerodynamic modifications reduce the strength of shedding vortex and increase rotor normal force through delaying and relieving flow separation, and therefore are beneficial to alleviate the limitation of control inputs. By contrast, the perturbation of unsteady ship airwake can cause the serious oscillation of rotor forces during shipboard landing. The unsteady simulations show that the turbulence intensity of ship airwake and oscillatory rotor airloading, represented by Root-Mean-Square(RMS) loading, can be remarkably reduced by the ramp and notch modifications, while the flap modification has adverse effect. It means that flow control devices have large potential benefits to alleviate the pilot's workload and improve the shipboard landing safety, but they should be well designed to avoid the introduction of more vortex, which leads to increase in disturbance of flow field.展开更多
We first analyzed the force and motion of naval aircraft during launching process.Further,we investigated the ship deck with the form of a ramp and established deck motion model and ship airwake model.Finally,we condu...We first analyzed the force and motion of naval aircraft during launching process.Further,we investigated the ship deck with the form of a ramp and established deck motion model and ship airwake model.Finally,we conducted simulations at medium sea.Results showed that the effects of deck motion on takeoff varied with initial phases,and airwake could help reducing aircraft′s sinkage.We also found that the deck motion played a major role in the effects caused by the interaction of deck motion and ship airwake.展开更多
基金supported by the Fundamental Research Funds for the Central Universities (No. NS2018007)
文摘A numerical study on flow control of ship airwake during shipboard landing is carried out to address the effect of flow control devices on helicopter rotor airload. The in-house Reynolds Averaged Navier-Stokes(RANS) based solver Rotorcraft AeroDynamics and Aeroacoustics Solver(RADAS), with combination of momentum source approach is employed to conduct the helicopter shipboard landing simulation. The control effects of three aerodynamic modifications of ship superstructure, i.e. ramp, notch and flap, in different Wind-Over-Deck(WOD) conditions are discussed.From the steady simulation results, the effect of spatial variation of ship airwake on rotor airloads is concluded. The aerodynamic modifications reduce the strength of shedding vortex and increase rotor normal force through delaying and relieving flow separation, and therefore are beneficial to alleviate the limitation of control inputs. By contrast, the perturbation of unsteady ship airwake can cause the serious oscillation of rotor forces during shipboard landing. The unsteady simulations show that the turbulence intensity of ship airwake and oscillatory rotor airloading, represented by Root-Mean-Square(RMS) loading, can be remarkably reduced by the ramp and notch modifications, while the flap modification has adverse effect. It means that flow control devices have large potential benefits to alleviate the pilot's workload and improve the shipboard landing safety, but they should be well designed to avoid the introduction of more vortex, which leads to increase in disturbance of flow field.
基金supported by the National Natural Science Foundation of China(No.61304223)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20123218120015)
文摘We first analyzed the force and motion of naval aircraft during launching process.Further,we investigated the ship deck with the form of a ramp and established deck motion model and ship airwake model.Finally,we conducted simulations at medium sea.Results showed that the effects of deck motion on takeoff varied with initial phases,and airwake could help reducing aircraft′s sinkage.We also found that the deck motion played a major role in the effects caused by the interaction of deck motion and ship airwake.
