Yoshikazu Makino

Design-Informatics Approach for Intimate Configuration of Silent Supersonic Technology Demonstrator

The intimate configuration of the silent supersonic technology demonstrator has been designed using the design-informatics approach. As a first step, multidisciplinary design optimization with multi-objectives has been performed for the wing shape of a silent supersonic technology demonstrator among aerodynamics, structures, aeroelasticity, and boom noise. Aerodynamic evaluation was carried out by solving Euler equations on computational fluid dynamics, and composite structural weight evaluation was performed by using MSC. NASTRAN for strength and flutter requirements on computational structural dynamics. The intensity of sonic boom was evaluated by a modified linear theory. The optimization problem had four objective functions as the minimizations of the pressure drag and the boom intensity at supersonic condition, and the composite structural weight. The intimate configuration defined by 50 design variables was optimized on particle swarm optimization and genetic algorithm hybrid method. In the structural evaluation, the combination optimization of stacking sequences of laminated composites was performed for inboard and outboard wings with strength and flutter requirements. Consequently, 37 non-dominated solutions were obtained. As a second step, data mining has been performed to obtain the design knowledge for deciding a compromise solution. The data mining revealed the knowledge in the design space, such as the tradeoff information among the objective functions, and the correlations between objective functions and design variables. A compromise solution was successfully determined by using the obtained design knowledge. Design-informatics approach is essential for an efficient design process.

Numerical Optimization of Fuselage Geometry to Modify Sonic-Boom Signature

A low-sonic-boom design method is developed by combining a three-dimensional Euler computational e uid dynamics code with a least-squares optimization technique. In this design method, the fuselage geometry of an aircraft is modie ed to minimize the pressure discrepancies between a target low-boom pressure signature and a calculated signature. The aircraft cone gurations that generate three types of low-boom pressure signatures, i.e., e attop type, ramp type, and hybrid type, are successfully designed by this method. It is shown that the sonic-boom intensity of the aircraft designed by linear theory is reduced and the e attop-type ground pressure signature is obtained by this method. The results of the study suggest that this method is a useful tool for low-boom design.

Evolutionary-Based Multidisciplinary Design Exploration for Silent Supersonic Technology Demonstrator Wing

Multidisciplinary design exploration with multiple objectives was performed for the wing shape of a silent supersonic technology demonstrator, considering aerodynamics, structures, and boom noise. Aerodynamic evaluation was carried out by solving Euler equations with computational fluid dynamics, and composite structural evaluation was performed by using Nastran for strength and vibration requirements with computational structural dynamics. The intensity of the sonic boom was evaluated by a modified linear theory. The optimization problem had five objective functions: minimization of the pressure and friction drags, boom intensity at the supersonic condition, and composite structural weight and maximization of the lift at the subsonic low-speed condition. The three-dimensional wing shape defined by 58 design variables was optimized with multi-objective particle swarm optimization and an adaptive-range multi-objective hybrid genetic algorithm method. In the structural evaluation, the combination optimization of stacking sequences of laminated composites was performed for inboard and outboard wings with strength and vibration requirements. Consequently, 75 nondominated solutions were efficiently obtained through 12 generations. Moreover, data mining was performed to obtain the design knowledge for deciding a compromise solution. The data mining revealed useful knowledge in the design space, such as the tradeoff information among the objective functions and the correlations between the objective functions and design variables. A compromise solution was successfully determined by using the obtained physical design knowledge.

Nonaxisymmetrical Fuselage Shape Modification for Drag Reduction of Low-Sonic-Boom Airplane

The effects of nonaxisymmetrical fuselage design for reducing the drag of a low-sonic-boom airplane are investigated by computational fluid dynamics (CFD) analyses and verified in wind-tunnel tests. The nonaxisymmetrical fuselage design, in which the upper side of a fuselage is designed for low drag whereas the lower side is designed for low sonic boom, is applied to the design of a Mach 1.7 scaled supersonic experimental airplane. The designed airplane is compared with a low-drag airplane and a low-sonic-boom airplane with an axisymmetrical fuselage

Fuselage Shape Optimization of a Wing-Body Configuration with Nacelles

An aerodynamic design tool that combines a computational e uid dynamics code with an optimization technique for a drag minimization is developed and applied to a fuselage shape optimization of a Mach 1.7 scaled supersonic experimental airplane. An airframe/nacelle integration is taken into consideration. The optimized fuselage is compared with a conventional axisymmetrical area-ruled fuselage designed by a lineartheory. The results indicate that a nonaxisymmetrical fuselage design concept with this optimization design tool iseffectivefor the reduction of pressuredrag,especially inthedesign ofan airplanethatgeneratesa strong interferencedrag between itsairframe and nacelles.

Multidisciplinary Design Exploration of Wing Shape for Silent Supersonic Technology Demonstrator

Multidisciplinary design exploration with multi-objectives has been performed for the wing shape of a silent supersonic technology demonstrator among aerodynamics, structures, and boom noise. Aerodynamic evaluation was carried out by using Euler computation on computational fluid dynamics, and composite structural evaluation was performed by using NASTRAN for strength and vibration requirements on computational structural dynamics. The intensity of sonic boom was evaluated by a modified linear theory. The optimization problem had five objective functions as the minimizations of the pressure/friction drags and the boom intensity at supersonic condition, and the composite structural weight as well as the maximization of the lift at subsonic condition. The three-dimensional wing shape defined by 58 design variables was optimized on particle swarm optimization and genetic algorithm hybrid method. In the structural evaluation, the combination optimization of stacking sequences of laminated composites was performed for in/outboard wings with strength and vibration requirements, respectively. Moreover, since the result of a multi-objective optimization problem is not a sole solution but an optimum set due to tradeoffs, data mining was performed to decide a compromise solution. Consequently, 75 non-dominated solutions were obtained. The data mining revealed the knowledge in the design space, such as the relations among the objectives, and the correlations among objectives and design variables. A compromise solution was determined through data mining.

Sonic Boom Prediction Using Multi-Block Structured Grids CFD Code Considering Jet-On Effects

CFD analyses with multi-block structured grids code are conducted in order to verify the low-boom design of the silent supersonic technology demonstrator airplane. The grid sensitivity study is conducted for high fidelity near-field pressure signature simulation to predict the sonic boom signature on the ground and an efficient fine computational mesh is determined through the study. Furthermore, the effects of the jet plume on sonic-boom are investigated through some jet-on simulations using the fine mesh. Direct effects of the jet plume on sonic-boom blow the airplane is relatively small compared to its indirect effects of changing aerodynamic forces and design angle-of-attack.

Supporting System Study of Wind-Tunnel Models for Validation of Aft-Sonic-Boom Shaping Design

Study on supporting system of wind-tunnel models for validating aft-sonic-boom shaping design technology is conducted in transonic wind-tunnel using several wind-tunnel models which are designed for low-boom. Two types of model supporting systems, a single sting and a twin sting support, are tested. Among these supporting systems for measuring near-field pressure signatures of a model, the twin sting support seems to be a promising system for validating some aft-sonic-boom shaping design concepts which are applied to the aft-part of an airplane, such as an aft-fuselage, engine nacelles and tail wings. The measured pressure data are also used to validate the low-boom design method based on the equivalent area theory and a near-field pressure prediction tool. I. Introduction UPERSONIC passenger aircrafts are promising for future airliners with the possibilities to meet the growing airlift demand and to liberate passengers from the pain due to long flight time. Various difficulties, however, prevent the civil aircrafts from flying at supersonic speeds after the Concorde’s retirement in 2003: The economically viable (low-weight, low-drag and high-efficient propulsion) and the environmentally friendly (lowsonic-boom, low-noise and low-emissions) characteristics are required for future supersonic airliners. Above all, sonic-boom is one of the most serious problems to be solved for supersonic overland flight. The Silent SuperSonic (S-cube) research program on quiet supersonic aircraft design technologies started in 2006 at Japan Aerospace Exploration Agency (JAXA). In this program, the Silent SuperSonic Technology Demonstrator (S 3 TD) [1] is planned to be built in order to demonstrate the advanced low-sonic-boom design technologies; low-boom design concepts and design/analysis tools. Recently, some flight demonstration programs for some low-boom design technologies have been conducted and they have shown some remarkable progresses [2-4]. The effectiveness of low-boom design technologies should be finally validated through these kinds of flight demonstrations. Meanwhile wind-tunnel test is still meaningful in the technology validation, at least in a preliminary phase of the flight demonstration programs. The wind-tunnel testing, however, have some problems in model supporting methods which have an influence on measuring near-field pressure signatures for validating the low-boom design concepts in particular the aft-part of signatures [5]. A windtunnel model designer should take into account these model/sting interference. This paper mainly discusses the wind-tunnel testing techniques especially the model supporting systems for validating the aft-sonic-boom shaping concepts and design. A twin-sting supporting system as well as a conventional single-sting supporting system is used in this study in order to show the possibility of validating aftsonic-boom shaping concepts. Aft-low-boom design concept and design tools are examined through the comparison between numerical prediction and wind-tunnel test data. The possibility of boom-shielding effect is also examined in this wind-tunnel test.

Design-informatics approach applicable to real-world problem

The design-informatics approach has been proposed for next-generation innovative design methodology. The multi-objective problem should be treated in a real-world engineering problem because of the various design requirements. When a multi-objective optimization is implemented, the obtained result is not a sole solution but a set of optimum solutions due to tradeoff relations among design requirements. Therefore, decision-making process is necessary as a post-process for optimization result. In the present study, the design-informatics approach, which is considered as a sequential process between an optimization and its post-process operations, is suggested and is applied to the large-scale and real-world design problem. Consequently, a compromised solution can be efficiently decided from the non-dominated solutions obtained by multidisciplinary design optimization. This approach would be a new efficient procedure for design manner, and also it would be the methodology that innovative design knowledge can be acquired.

Sonic-Boom Prediction of a Scaled Low-Boom Demonstration Aircraft Considering Viscosity Effects

Viscosity effects in sonic-boom prediction are investigated using inviscid and viscous CFD analysis for estimating near-field pressure signatures of a scaled low-boom demonstration aircraft. A structured/unstructured overset grids method used with Euler CFD analysis is extended to Navier-Stokes analysis for this study. A viscosity effect is shown in the near-field pressure signatures especially in the wing part as a wing thickness effect. This study suggests that the viscosity effects are not critical in low-boom design even for a scaled airplane with small Reynolds number.