Masahiko Sugiura

Accuracy Estimation of Probabilistic Wake Vortex Prediction Considering Weather Information Errors

Current wake vortex separation minima are a major impediment to increasing traffic capacity since they require greater separations than radar separation minima. The concept of dynamic wake vortex separation minima, which would allow reduced separations in favorable meteorological conditions when wake durations on flight paths become shorter, would allow an increase in capacity. This paper proposes a methodology that uses a probabilistic wake vortex prediction model to probabilistically assure that wake vortex encounter risks at reduced separations are equal or lower than the risks at current separations.

Airport Terminal Traffic Simulation Applying Reduced Wake Vortex Separation

The Japan Aerospace Exploration Agency has developed an airport terminal traffic simulation environment that dynamically minimizes aircraft wake vortex separation by considering wake vortex behaviors from meteorological information and using GBAS-based curved approach paths. A traffic simulation of Tokyo International airport using four intersecting runways revealed that the capacity could be increased by up to 12% by reducing separations without additional risk of wake vortex encounter. This result demonstrates the benefit to airport capacity of reducing wake vortex separations dynamically.

Numerical Simulations and Measurements of the Helicopter Wake in Ground Effect

When a helicopter takes off, lands, or makes hovering or taxiing flights in ground effect, its downwash interferes with the ground. Encounters with such highly turbulent helicopter wakes have resulted in the two small fixed-wing aircraft crashes in the United Kingdom. Due to these accidents, the Japan Aerospace Exploration Agency is investigating the helicopter wake structure in ground effect, especially during taxiing, by means of computational fluid dynamics and flight testing. The base computational fluid dynamics code is structured grid solver rFlow3D, which has systematically been developed for helicopter applications at the Japan Aerospace Exploration Agency. The rFlow3D solver is a highly versatile computational fluid dynamics code that can numerically simulate flows around helicopters with a wide range of Reynolds and Mach numbers and can perform rotor trim analysis with elastic blade deformations. In the flight experiment described herein, the Japan Aerospace Exploration Agency research helicopte...

Hybrid surrogate-model-based multi-fidelity efficient global optimization applied to helicopter blade design

ABSTRACT A multi-fidelity optimization technique by an efficient global optimization process using a hybrid surrogate model is investigated for solving real-world design problems. The model constructs the local deviation using the kriging method and the global model using a radial basis function. The expected improvement is computed to decide additional samples that can improve the model. The approach was first investigated by solving mathematical test problems. The results were compared with optimization results from an ordinary kriging method and a co-kriging method, and the proposed method produced the best solution. The proposed method was also applied to aerodynamic design optimization of helicopter blades to obtain the maximum blade efficiency. The optimal shape obtained by the proposed method achieved performance almost equivalent to that obtained using the high-fidelity, evaluation-based single-fidelity optimization. Comparing all three methods, the proposed method required the lowest total number of high-fidelity evaluation runs to obtain a converged solution.