Numerical Wind Tunnel Research Articles

特集 宇宙往環機開発における風洞／ＣＦＤの役割 スペースプレーンの超音速数値シミュレーションと風洞試験

特集 宇宙往環機開発における風洞／ＣＦＤの役割 スペースプレーンの超音速数値シミュレーションと風洞試験

Subharmonic bifurcation analysis of wing with store flutter

An approximate method is developed to analyze the subharmonic bifurcation of a wing with a store aeroelastic system, of which the junction stiffness is piecewise linear. The key point is to treat the store as a forced oscillator under harmonic excitation exerted through the junction from the wing in limit cycle flutter states. Then the criteria with respect to excitation frequency can be applied to predict subharmonic bifurcation. Both numerical integration and wind tunnel tests show that the approximate approach is feasible.

Numerical Wind Tunnel Project at National Aerospace Laboratory

Numerical Wind Tunnel Project at National Aerospace Laboratory

Spray droplet generation, transport, and evaporation in a wind wave tunnel during the humidity exchange over the sea experiments in the simulation tunnel

The HEXOS Experiments In the Simulation Tunnel (HEXIST) are part of the continuing Humidity Exchange Over the Sea program (HEXOS). It is actually an international cooperative subprogram focused on the local interactions between spray droplets and the turbulent fields of velocity, temperature, and humidity. It incorporates numerical modelling and wind tunnel experiments. In order to study separately the generation of droplets, their transport and diffusion by turbulence, their evaporation, and their deposition, a new experimental approach has been designed, based on the generation of spray droplets by the bursting of bubbles produced by aeration devices immersed in the water tank of the large air‐sea interaction simulation tunnel at the Institut de Mécanique Statistique de la Turbulence, Marseille, France. This paper presents this approach, the experimental setup, the governing equations, and the results of the feasibility experiments.

山越え温度成層流中のガス拡散に関する数値計算と風洞実験

山越え温度成層流中のガス拡散に関する数値計算と風洞実験

Study on wind environmental problems caused around buildings in Japan

This paper deals with wind environmental problems around buildings which, recently, have given cause for concern in Japan. We will consider the general trend of handling such problems, and a short history of how such problems came into being will be presented. Full-scale test data and wind tunnel test data obtained during research into these problems will also be explained. Full-scale test data used in this paper and those obtained at the Shinjuku Development Area, where a number of skyscrapers now stand, and their similarity with wind tunnel test data, will be discussed. Moreover, numerous basic wind tunnel test data relating to the strong wind region in particular will be considered. Following this, a discussion of a wind environment method applicable to strong wind regions is presented.