Sonic boom reduction has been an urgent need for the development of future supersonic transport,because of the heavy damage of noise pollution.This paper provides a novel concept for supersonic aircraft to reduce the ...Sonic boom reduction has been an urgent need for the development of future supersonic transport,because of the heavy damage of noise pollution.This paper provides a novel concept for supersonic aircraft to reduce the sonic boom and drag coefficient,wherein a suction slot near the leading edge and an injection slot near the trailing edge on the airfoil suction surface are opened.To make sure of a zero net mass flux flow control,the mass flow sucked in near the leading edge is equal to the mass flow injected near the trailing edge.The diamond and NACA0008 airfoils are adopted as the baseline airfoil to verify the capability of the proposed design method.The effects of the suction and injection location,the suction and injection slot size,the mass flow rate and the attack angle on the ground boom signature and drag coefficient are studied in detail.The results show that the optimized airfoils with the suction and injection have benefits in both sonic boom reduction and wave drag reduction.And the reduction of the sonic boom intensity is more sensitive to the injection near the trailing edge than the suction near the leading edge.From the viewpoint of aerodynamics,opening the suction and injection slots will have no adverse effect on the aerodynamic performances of the supersonic aircraft and even increase the lift-drag ratio under some circumstances.For energy saving,the suction and injection slots can be selectively opened,which are opened when the supersonic aircraft flies over the city but are closed when the aircraft flies over the sea.展开更多
The article represents the discussion of several separate directions of investigations,which are performed by TsAGI flight vehicles aerodynamics specialists at the time.There are some major trends of classical layout ...The article represents the discussion of several separate directions of investigations,which are performed by TsAGI flight vehicles aerodynamics specialists at the time.There are some major trends of classical layout of route aircraft and also peculiarities of some prospective flight vehicles.Also there are some hypersonic vehicles aerodynamics questions examined along with problems of creation of civil supersonic transport aircraft.There is a description given for well-known and some newer methods of flow control for drag reduction.展开更多
Mitigation of sonic boom to an acceptable stage is a key point for the next generation of supersonic transports. Meanwhile, designing a supersonic aircraft with an ideal ground signature is always the focus of researc...Mitigation of sonic boom to an acceptable stage is a key point for the next generation of supersonic transports. Meanwhile, designing a supersonic aircraft with an ideal ground signature is always the focus of research on sonic boom reduction. This paper presents an inverse design approach to optimize the near-field signature of an aircraft, making it close to the shaped ideal ground signature after the propagation in the atmosphere. Using the Proper Orthogonal Decomposition(POD) method, a guessed input of augmented Burgers equation is inversely achieved. By multiple POD iterations, the guessed ground signatures successively approach the target ground signature until the convergence criteria is reached. Finally, the corresponding equivalent area distribution is calculated from the optimal near-field signature through the classical Whitham F-function theory. To validate this method, an optimization example of Lockheed Martin 1021 is demonstrated. The modified configuration has a fully shaped ground signature and achieves a drop of perceived loudness by 7.94 PLdB. This improvement is achieved via shaping the original near-field signature into wiggles and damping it by atmospheric attenuation. At last, a nonphysical ground signature is set as the target to test the robustness of this inverse design method and shows that this method is robust enough for various inputs.展开更多
基金supported by the National Natural Science Foundation of China(Grants No.11732013)the National Numerical Windtunnel project(NNW2019ZT3-A15).
文摘Sonic boom reduction has been an urgent need for the development of future supersonic transport,because of the heavy damage of noise pollution.This paper provides a novel concept for supersonic aircraft to reduce the sonic boom and drag coefficient,wherein a suction slot near the leading edge and an injection slot near the trailing edge on the airfoil suction surface are opened.To make sure of a zero net mass flux flow control,the mass flow sucked in near the leading edge is equal to the mass flow injected near the trailing edge.The diamond and NACA0008 airfoils are adopted as the baseline airfoil to verify the capability of the proposed design method.The effects of the suction and injection location,the suction and injection slot size,the mass flow rate and the attack angle on the ground boom signature and drag coefficient are studied in detail.The results show that the optimized airfoils with the suction and injection have benefits in both sonic boom reduction and wave drag reduction.And the reduction of the sonic boom intensity is more sensitive to the injection near the trailing edge than the suction near the leading edge.From the viewpoint of aerodynamics,opening the suction and injection slots will have no adverse effect on the aerodynamic performances of the supersonic aircraft and even increase the lift-drag ratio under some circumstances.For energy saving,the suction and injection slots can be selectively opened,which are opened when the supersonic aircraft flies over the city but are closed when the aircraft flies over the sea.
文摘The article represents the discussion of several separate directions of investigations,which are performed by TsAGI flight vehicles aerodynamics specialists at the time.There are some major trends of classical layout of route aircraft and also peculiarities of some prospective flight vehicles.Also there are some hypersonic vehicles aerodynamics questions examined along with problems of creation of civil supersonic transport aircraft.There is a description given for well-known and some newer methods of flow control for drag reduction.
文摘Mitigation of sonic boom to an acceptable stage is a key point for the next generation of supersonic transports. Meanwhile, designing a supersonic aircraft with an ideal ground signature is always the focus of research on sonic boom reduction. This paper presents an inverse design approach to optimize the near-field signature of an aircraft, making it close to the shaped ideal ground signature after the propagation in the atmosphere. Using the Proper Orthogonal Decomposition(POD) method, a guessed input of augmented Burgers equation is inversely achieved. By multiple POD iterations, the guessed ground signatures successively approach the target ground signature until the convergence criteria is reached. Finally, the corresponding equivalent area distribution is calculated from the optimal near-field signature through the classical Whitham F-function theory. To validate this method, an optimization example of Lockheed Martin 1021 is demonstrated. The modified configuration has a fully shaped ground signature and achieves a drop of perceived loudness by 7.94 PLdB. This improvement is achieved via shaping the original near-field signature into wiggles and damping it by atmospheric attenuation. At last, a nonphysical ground signature is set as the target to test the robustness of this inverse design method and shows that this method is robust enough for various inputs.
