Takashi Matsuno

Aerodynamic Control of High Performance Aircraft Using Pulsed Plasma Actuators

The active flow control technology to manipulate forebody vortices on a slender tangent ogive nose body is being developed. The plasma actuators are being used to exploit the bistable nature of the asymmetric forebody vortex wake for lateral/directional control in lowspeed and high-angle-of attack regimes. The experiments have confirmed that the plasma actuator can be used to displace the vortex on the forebody model by the Coanda effect. The results of the force and moment measurement indicate that this displacement could successfully generate significant change in their side force, which could be utilized to extend maneuvering flight envelop for future fighter designs. High speed visualization data show that there is strong time lag in the response of the vortex motion, and multi-parameter coupling to determine the effect of the actuation is suggested.

Jet Vectoring and Enhancement of Flow Control Performance of Trielectrode Plasma Actuator Utilizing Sliding Discharge

The flow control performance and jet vectoring characteristics of trielectrode (TED) plasma actuators on quiescent air were analyzed. To examine the body force generated from the actuator, the thrust of the induced jet was measured, as a reaction of the aerodynamic force from the actuator. The corresponding induced jet was visualized by means of highspeed Schrielen Visualization with the discharge conditions to understand physical phenomena on the actuator. The experiments show that the thrust generated by the TED actuator depended on the applied DC voltage. By applying high negative DC voltage, with the existence of sliding discharge channels between the two exposed electrodes, the induced flow becomes in the pronounced vertical jet. The overall thrust is greatly improved from SDBD actuator at these regimes. The efficiency of SDBD actuator also shows substantial improvement. These confirm that the TED actuator could improve both body force and their power efficiency at the same time.

Parameter Design Optimization of Plasma Actuator Configuration for Separation Control

The performance of the plasma actuators for wake control and resulting drag reduction is examined and the optimization of the driving conditions of the plasma actuators were carried out by using the robust design method for wake control at high dynamic pressure conditions. The parameter design method that we used is feasible for the optimization of the control variables for flow control, under the situation that has multiple input parameters, requiring robustness, and complexity in flow phenomenon. The result of the design method gives the predicted optimal condition for reduced control parameters and that is confirmed to be robust and stable to the application test.

Position and attitude control of an underactuated satellite with constant thrust

This paper discusses a position and attitude control problem of an underactuated satellite which uses on-off thruster mechanisms for control. Each thrusters has constant orientation relative to the satellite’s body, and can generate only unilateral forces. The purpose of this paper is to clarify the control law for simultaneous position and attitude control for this type of satellite configuration. Considering the input constraints, we obtain the analytical solutions of the satellite’s translational and rotational motion. Then the control procedure utilizing an invariant manifold is derived. Some numerical simulations are shown to verify the effectiveness of the proposed controller.

Unsteady aerodynamics of rolling thick delta wing with high aspect ratio

The objective of the present study is to experimentally examine rolling aerodynamics of a thick and relatively high aspect ratio delta wing. First, static aerodynamic forces of lift, drag, and pitching and rolling moments were measured with a sting balance with six force components. At an attack angle where lift becomes maximum, the wing was found to be unstable with regard to roll motion. Under post-stall conditions, highly non-linear characteristics were observed, and at some angles of attack, there exist several equilibrium points with regard to roll angle except for = 0°. Then, rolling transitional processes were examined by free-to-roll tests using a potentiometer to see the effects of unsteady aerodynamics. As a result, unsteady phenomena like wing rock were observed around several equilibrium points except for = 0°. Though these phenomena are self-induced oscillations, their mechanism seems to be different from wing rock oscillation. Nomenclature b wing span cr root chord

Efficient global optimization applied to wind tunnel evaluation-based optimization for improvement of flow control by plasma actuators

A kriging-based genetic algorithm called efficient global optimization (EGO) was employed to optimize the parameters for the operating conditions of plasma actuators. The aerodynamic performance was evaluated by wind tunnel testing to overcome the disadvantages of time-consuming numerical simulations. The proposed system was used on two design problems to design the power supply for a plasma actuator. The first case was the drag minimization problem around a semicircular cylinder. In this case, the inhibitory effect of flow separation was also observed. The second case was the lift maximization problem around a circular cylinder. This case was similar to the aerofoil design, because the circular cylinder has potential to work as an aerofoil owing to the control of the flow circulation by the plasma actuators with four design parameters. In this case, applicability to the multi-variant design problem was also investigated. Based on these results, optimum designs and global design information were obtained while drastically reducing the number of experiments required compared to a full factorial experiment.

Physical Mechanism of Tri-Electrode Plasma Actuator with Direct-Current High Voltage

Tri-electrode plasma actuator (TED-PA), which has a third electrode with DC high voltage, can generate stronger jet than that of conventional two-electrode plasma actuator. However, the behavior of...

Development of Serrated Multi-Electrode Plasma Actuators for Enhanced Force Production

The advantage in the thrust performance of the trielectode (TED) plasma actuator with serrated electrode edge was investigated. The trielectrode actuators have an additional exposed electrode, to which high DC voltage is applied, on the opposite edge of the buried electrode of the exposed AC electrode of SDBD plasma actuator. To prevent the uneven distributions of the discharge, the intentional dent that is evenly spaced on the exposed electrode was introduced. In this research, the induced body force of the TED plasma actuator was investigated on quiescent air by measuring thrust of the induced jet. A timeresolved PIV was used to acquire a velocity field in the quiescent air to measure the induced jet structure. To clarify the performance improvement mechanism, discharge plasma and flow field were numerically simulated. From the results of the thrust measurement, it is confirmed that the serrated TED plasma actuator enhances the thrust compared to the straight-edge TED plasma actuator especially at high DC voltage regimes. The absolute thrust attained 82.7mN/m, which was about 2.1 times larger than the straight-edge TED actuator and 17.5 times larger than the standard SDBD plasma actuator at the same conditions. The power efficiency became twice of the straight-edge TED plasma actuator and more than six times better than the SDBD plasma actuator at the same time. The PIV analysis clearly show that the serrated TED plasma actuator generate a uniform pattern of facing jet from both of the electrode for the positive DC voltage case, because of the uniform generation of the plasma from the sawtooth vertexes. For the negative DC voltage case, the uniformity of the induced flow was not improved.

Development of Trielectrode Plasma Actuator and Its Application to Delta Wing Vortex Control

The flow control performances of the trielectrode plasma actuators are examined. By the balance measurement the TED-DBD (positive DC voltage was applied to the additional electrode) actuator enhances the thrust as the DC voltage increase, and the maximum thrust for the TED-DBD reaches 270% of the one for the SDBD actuator in the same conditions. The TED-SD (negative DC voltage to the additional electrode) actuator generates strong negative thrust up to 400% of SDBD case. The TED-SD actuator generated recirculation bubble on the electrode. The recirculation area becomes expanded and diverts their direction upward and reversed as the DC voltage increases. For the delta wing vortex control, the TED-SD plasma actuator was found to be feasible to control the flows that include massive three dimensional separations. The change in the direction of the induced jet generates peculiar control performance of the flow. Nomenclature fac = frequency of the AC voltage T = Thrust generated by plasma actuator Vax = AC voltage applied to the DBD electrode of plasma actuator, peak-to-peak Vdc = DC voltage applied to the Third (DC) electrode of plasma actuator

Multiple Additional Sampling by Expected Improvement Maximization in Efficient Global Optimization for Real-World Design Problems

Efficient global optimization (EGO), based on the expected improvement maximization of the Kriging model, is a suitable optimization method for designs based on time-consuming evaluations such as computational fluid dynamics. However, the original formulation of EGO can find only one additional sample point after an initial sample point is acquired for the initial Kriging model construction. Therefore, the efficiency of EGO is decreased even if the designer is able to evaluate several designs using a large parallel computer because additional samples can only be obtained sequentially through the additional sampling process. In this study, a multiple additional sampling method is proposed to improve the efficiency of the additional sampling process in EGO while maintaining the performance of exploration based on EI maximization. The design performance of EGO with MAS is investigated by solving a test problem first, and then an airfoil design problem, which is a single objective problem. The results are compared with the original EGO in terms of the convergence of the objective function and the diversity of the design variables. According to these problems, the proposed method acquires optimum solutions as effectively as the original EGO, while the diversity of the solutions is improved. In addition, the total design time can be reduced compared with the original EGO in a parallel computational environment.