Numerical investigation of natural transitions of bow boundary layers over underwater axisymmetric bodies

2021 ◽  
Vol 33 (7) ◽  
pp. 074101
Author(s):  
Jingcheng Liu ◽  
Xuesen Chu ◽  
Yongming Zhang
Keyword(s):  
Numerical Investigation ◽  
Boundary Layers ◽  
Axisymmetric Bodies

Review: Laminar-to-Turbulent Transition of Three-Dimensional Boundary Layers on Rotating Bodies

1994 ◽  
Vol 116 (2) ◽  
pp. 200-211 ◽  
Author(s):  
Ryoji Kobayashi
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Three Dimensional ◽  
Speed Ratio ◽  
Stream Velocity ◽  
Turbulent Transition ◽  
Centrifugal Instability ◽  
Crossflow Instability ◽  
Dimensional Boundary ◽  
Axisymmetric Bodies

The laminar-turbulent transition of three-dimensional boundary layers is critically reviewed for some typical axisymmetric bodies rotating in still fluid or in axial flow. The flow structures of the transition regions are visualized. The transition phenomena are driven by the compound of the Tollmien-Schlichting instability, the crossflow instability, and the centrifugal instability. Experimental evidence is provided relating the critical and transition Reynolds numbers, defined in terms of the local velocity and the boundary layer momentum thickness, to the local rotational speed ratio, defined as the ratio of the circumferential speed to the free-stream velocity at the outer edge of the boundary layer, for the rotating disk, the rotating cone, the rotating sphere and other rotating axisymmetric bodies. It is shown that the cross-sectional structure of spiral vortices appearing in the transition regions and the flow pattern of the following secondary instability in the case of the crossflow instability are clearly different than those in the case of the centrifugal instability.

Numerical Investigation of Supersonic Dense-Gas Boundary Layers

2020 ◽  
pp. 91-103
Author(s):  
Luca Sciacovelli ◽  
Donatella Passiatore ◽  
Xavier Gloerfelt ◽  
Paola Cinnella ◽  
Francesco Grasso
Keyword(s):  
Numerical Investigation ◽  
Boundary Layers ◽  
Dense Gas
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