入口に障害物を置いた流路内に生じる逆流の数値解析

Reverse flow occurs in a channel when an obstruction is placed at the entry. The phenomenon involves separation, reattachment and shear layer interaction. The various facets of the phenomenon have earlier been investigated experimentally. Presently, an attempt has been made to compute this flow solving unsteady equations of motion. Preliminary results do predict the occurance of reverse flow.流路入口に障害物を設置すると、流路内部に逆流が生じる。この現象は、はく離、再付着および剪断流れの干渉を含む。この現象については様々な観点から多くの実験的な研究がなされてきた。近年の数値流体解析技術の進歩により、このような非定常流れを解析することが可能となっており、本研究では逆流の挙動を究明するための第一段階の解析を行った

前方入口に障害物を置いた流路内に生じる逆流の数値解析

Reverse flow occurs in a channel when an obstruction is placed at the entry. The phenomenon involves separation, reattachment and shear layer interaction. The various facets of the phenomenon have earlier been investigated experimentally. Presently, an attempt has been made to compute this flow both steady and unsteady equations of motion. Results predict the occurrence of reverse flow, and bring out other features of flow like vortex shedding behind the channel.流路入口に障害物を設置すると、流路内部に逆流が生じる。この現象は、はく離、再付着およびせん断流れの干渉を含む。この現象については、様々な観点から多くの実験的な研究がなされてきた。本研究では、逆流の挙動を解明するため、CFD(computational Fluid Dynamics)により解析した。それらの結果は、逆流の発生を予測し、壁面後方に影響を及ぼす渦のような流れの特徴を示している

PIV studies on reverse flow in a channel without obstruction at the entry

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.It is known that reverse flow (i.e. flow in the direction opposite to the free stream) occurs when an obstruction is placed near the entry region of a channel (referred to as the test channel), kept inside another wider channel. The present investigation is focused on realizing reverse flow in the test channel without an obstruction placed at the entry. Experiments in water channel have been carried out along with visualization of the flow using PIV. The initial stages of the investigation revealed that the test channel with the two walls, forming the channel having a stagger with respect to each other and at an angle of attack would result in reverse flow even without an obstruction. Studies have been carried out for different widths (gap between the two walls forming the channel), and at an angle of attack of 30⁰.cs201