摘要
The pressure distribution around a near-wall smooth circular cylinder incross-flow was mainly investigated. The experiment was conducted at the sub-critical Reynolds numberranging from 2. 24 · 10~4 to 8. 94 · 10~4, at which the regular vortex separation exists on anisolated circular cylinder. The experimental results indicate that the forces on a circular cylindernear a plane wall are different from those on an isolated circular cylinder. Drag and liftcoefficients of a near-wall circular cylinder strongly depend on gap ratio. The increase of gapratio results in the increase of drag coefficient and the declination of lift coefficient, dragcoefficient ranges from 0. 5 to 1. 0, and lift coefficient from 0. 25 to 0 when gap ratio graduallyincreases from 0 to 1. 0, and then the forces tend to be nearly constant with the increase of gapratio. The attraction between a cylinder and a plane wall, i. e. , downward force, occurs when gapratio lies in certain range. The existence of cylinder changes the pressure gradient on the planewall, and the influence extends to the location where x/D 【 - 3.0 and x/D 】 5. 0 .
The pressure distribution around a near-wall smooth circular cylinder incross-flow was mainly investigated. The experiment was conducted at the sub-critical Reynolds numberranging from 2. 24 · 10~4 to 8. 94 · 10~4, at which the regular vortex separation exists on anisolated circular cylinder. The experimental results indicate that the forces on a circular cylindernear a plane wall are different from those on an isolated circular cylinder. Drag and liftcoefficients of a near-wall circular cylinder strongly depend on gap ratio. The increase of gapratio results in the increase of drag coefficient and the declination of lift coefficient, dragcoefficient ranges from 0. 5 to 1. 0, and lift coefficient from 0. 25 to 0 when gap ratio graduallyincreases from 0 to 1. 0, and then the forces tend to be nearly constant with the increase of gapratio. The attraction between a cylinder and a plane wall, i. e. , downward force, occurs when gapratio lies in certain range. The existence of cylinder changes the pressure gradient on the planewall, and the influence extends to the location where x/D < - 3.0 and x/D > 5. 0 .
