Research of low boom and low drag supersonic aircraft design

Sonic boom reduction will be an issue of utmost importance in future supersonic trans-port, due to strong regulations on acoustic nuisance. The paper describes a new multi-objective optimization method for supersonic aircraft design. The method is developed by coupling Seebass-George-Darden （SGD） inverse design method and multi-objective genetic algorithm. Based on the method, different codes are developed. Using a computational architecture, a concep-tual supersonic aircraft design environment （CSADE） is constructed. The architecture of CSADE includes inner optimization level and out optimization level. The low boom configuration is gener-ated in inner optimization level by matching the target equivalent area distribution and actual equivalent area distribution. And low boom/low drag configuration is generated in outer optimiza-tion level by using NSGA-II multi-objective genetic algorithm to optimize the control parameters of SGD method and aircraft shape. Two objective functions, low sonic boom and low wave drag, are considered in CSADE. Physically reasonable Pareto solutions are obtained from the present optimization. Some supersonic aircraft configurations are selected from Pareto front and the optimization results indicate that the swept forward wing configuration has benefits in both sonic boom reduction and wave drag reduction. The results are validated by using computational fluid dynamics （CFD） analysis.

A low-boom and low-drag design method for supersonic aircraft and its applications on airfoils

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.

Modern problems of aircraft aerodynamics

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.

Coupled funnel control for supersonic tailless aerial vehicle on penetrating counter air

Supersonic Tailless Aerial Vehicles(STAVs)will become an essential force in Penetrating Counter Air(PCA),but STAVs do not have the traditional horizontal and vertical tails,making pitch and yaw control difficult.The attack angle and the sideslip angle need to be limited to ensure that the engine inlet and the aerodynamic rudder at the rear of the vehicle can work properly,which is the so-called security constraints.In addition,the tracking error of the aerodynamic angle needs to be limited to achieve effective attitude control or high-accuracy tracking of trajectories,which is the so-called performance constraints.To this end,an attitude control method that meets the needs of PCA has been devised,based on constraint definition,coupled constraints handling,and control law design.Firstly,mathematical descriptions of the security constraints,performance constraints,and control constraints are given.Secondly,two treatment methods,coupled command filter and coupled funnel control are proposed for the aerodynamic angle coupled constraint problem.Finally,based on Nonlinear Dynamic Inverse(NDI)design,the coupled funnel controller is designed and validated by simulation for two typical mission scenarios,high-altitude penetration and low-altitude surprise defence.The proposed control method not only satisfies the security and performance constraints of STAV attitude control but also is highly robust.