| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1987: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1986: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Considerations are made on the flow distortion resulting from two kinds of obstacle, which extends across a narrow channel. They are a jet issuing normally into a cross flow from a channel wall and a cylinder spanned between channel walls.
1. On the jet (1) Analyses ---- The following are discussed, namely, effects of a wall boundary layer on a trajectory of the jet issuing across the boundary layer f a trajectory of the jet impinging on the channel wall ; a circulation along the vortexlike flow induced by the jet ; aerodynamic wall-interference effects and a trajectory of the jet. The calculated and experimental jet-trajectories agree fairly good. The calculated circulation is near experiments, especially at low velocity ratios. The distortion of the velocity field can be calculated using Biot-Savart's law, together with the vortex center line and the circulation along it. The calculated velocity distributions agree quontitatively with experiments. (2) Experiments ---- Considerations a
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re made on a three-dimensional flow, which results from both a vortexlike flow induced by the jet impinging on a channel wall and aerodynamic interference effects due to the vortexlike flow and the channel wall. The result gives new knowledges on a variation of the maximum velocity along the jet center line, a location of the vortex center line downstream of an impinging point of the jet, and a flow pattern on the channel wall, on which the jet impinges.
2. On the cylinder (1) Experiments ---- The flow distortion due to the cylinder, a channel-wall boundary layer and aerodynamic wall-interference effects is considered. Velocity vectors are measured with the hot-wire anemometer. The necklacelike vortex as a secondary flow isn't clear, because of a small wall-boundary-layer thickness. However, the results reveal that there is the interference effects due to the cylinder and the wall boundary layer, especially the marked effects on the lateral velocity component. Topics for further investigation are to derive an empirical expression for trajectories of the necklacelike vortex and to improve a hot-wire technique for measurements of velocity vector with large fluctuations. Less
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