The influence of inner-wall motion on the linear stability of natural convection in a tall vertical annulus

✍ Scribed by J.-C. Chen; G.-H. Chou; C.-K. Hsieh

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 630 KB
• Volume: 39
• Category: Article
• ISSN: 0017-9310
• DOI: 10.1016/s0017-9310(96)85015-0

✦ Synopsis

The linear stability of natural convection in a tall vertical annulus with inner-cylinder motion was studied. The results show that the stability characteristics are significantly modified by the innercylinder motion. For a small Prandtl number fluid with a smaller radius ratio. the shear instability is dominant and the non-axisymmetric disturbance (nt = I) is most unstable no matter in which direction the inner cylinder is moving. For higher downward motion, the non-axisymmetric mode (IPI = 2) may replace modes m = 0 and I for some radius ratios. For higher Prandtl number fluids. the most unstable mechanism switches from a buoyant mode generated by the boundary layer near the outer cylinder to a buoyant mode induced by the boundary layer near the inner cylinder with an increase of curvature as the inner cylinder is moving.