Numerical Simulation of Single Argon Bubble Rising in Molten Metal Under a Laminar Flow

2015 ◽  
Vol 86 (11) ◽  
pp. 1289-1297 ◽  
Author(s):  
Yonggui Xu ◽  
Mikael Ersson ◽  
Pär Jönsson
Keyword(s):  
Numerical Simulation ◽  
Laminar Flow ◽  
Molten Metal ◽  
Argon Bubble ◽  
Bubble Rising

scholarly journals Laminar Mixing in Stirred Tank Agitated by an Impeller Inclined

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Koji Takahashi ◽  
Yoshiharu Sugo ◽  
Yasuyuki Takahata ◽  
Hitoshi Sekine ◽  
Masayuki Nakamura
Keyword(s):  
Numerical Simulation ◽  
Laminar Flow ◽  
Mixing Time ◽  
Flow Region ◽  
Experimental Results ◽  
Stirred Tank ◽  
Simulation Methods ◽  
Mixing Performance ◽  
Laminar Mixing ◽  
Numerical Simulation Methods

The mixing performance in a vessel agitated by an impeller that inclined itself, which is considered one of the typical ways to promote mixing performance by the spatial chaotic mixing, has been investigated experimentally and numerically. The mixing time was measured by the decolorization method and it was found that the inclined impeller could reduce mixing time compared to that obtained by the vertically located impeller in laminar flow region. The effect of eccentric position of inclined impeller on mixing time was also studied and a significant reduction of mixing time was observed. To confirm the experimental results, the velocity profiles were calculated numerically and two novel numerical simulation methods were proposed.

Numerical simulation of the evolution of Tollmien–Schlichting waves over finite compliant panels

1997 ◽  
Vol 335 ◽  
pp. 361-392 ◽  
Author(s):  
CHRISTOPHER DAVIES ◽  
PETER W. CARPENTER
Keyword(s):  
Numerical Simulation ◽  
Laminar Flow ◽  
Stokes Equations ◽  
Plane Channel ◽  
Solution Procedure ◽  
Good Prospect ◽  
Flow Perturbation ◽  
Compliant Wall ◽  
Compliant Walls ◽  
Tollmien Schlichting

The evolution of two-dimensional Tollmien–Schlichting waves propagating along a wall shear layer as it passes over a compliant panel of finite length is investigated by means of numerical simulation. It is shown that the interaction of such waves with the edges of the panel can lead to complex patterns of behaviour. The behaviour of the Tollmien–Schlichting waves in this situation, particularly the effect on their growth rate, is pertinent to the practical application of compliant walls for the delay of laminar–turbulent transition. If compliant panels could be made sufficiently short whilst retaining the capability to stabilize Tollmien–Schlichting waves, there is a good prospect that multiple-panel compliant walls could be used to maintain laminar flow at indefinitely high Reynolds numbers.We consider a model problem whereby a section of a plane channel is replaced with a compliant panel. A growing Tollmien–Schlichting wave is then introduced into the plane, rigid-walled, channel flow upstream of the compliant panel. The results obtained are very encouraging from the viewpoint of laminar-flow control. They indicate that compliant panels as short as a single Tollmien–Schlichting wavelength can have a strong stabilizing effect. In some cases the passage of the Tollmien–Schlichting wave over the panel edges leads to the excitation of stable flow-induced surface waves. The presence of these additional waves does not appear to be associated with any adverse effect on the stability of the Tollmien–Schlichting waves. Except very near the panel edges the panel response and flow perturbation can be represented by a superposition of the Tollmien–Schlichting wave and two other eigenmodes of the coupled Orr–Sommerfeld/compliant-wall eigensystem.The numerical scheme employed for the simulations is derived from a novel vorticity–velocity formulation of the linearized Navier–Stokes equations and uses a mixed finite-difference/spectral spatial discretization. This approach facilitated the development of a highly efficient solution procedure. Problems with numerical stability were overcome by combining the inertias of the compliant wall and fluid when imposing the boundary conditions. This allowed the interactively coupled fluid and wall motions to be computed without any prior restriction on the form taken by the disturbances.

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