Laser velocimetry measurements in a high density ratio supersonic shear layer

1997 ◽  
Author(s):  
Jay Hammer ◽  
Roland Anderson ◽  
Rodney Clark ◽  
James Gordon, III ◽  
Jay Hammer ◽  
...  
Keyword(s):  
Shear Layer ◽  
Density Ratio ◽  
High Density ◽  
Laser Velocimetry ◽  
High Density Ratio

A Combined Volume of Fluid and Immersed Boundary Method for Modelling of Two-Phase Flows with High Density Ratio

2021 ◽  
Author(s):  
Qiu Jin ◽  
Dominic Hudson ◽  
W.G. Price
Keyword(s):  
Boundary Layer ◽  
Immersed Boundary Method ◽  
Density Ratio ◽  
Volume Of Fluid ◽  
High Density ◽  
Immersed Boundary ◽  
Two Phase Flows ◽  
Two Phase ◽  
Boundary Method ◽  
High Density Ratio

Abstract A combined volume of fluid and immersed boundary method is developed to simulate two-phase flows with high density ratio. The problems of discontinuity of density and momentum flux are known to be challenging in simulations. In order to overcome the numerical instabilities, an extra velocity field is designed to extend velocity of the heavier phase into the lighter phase and to enforce a new boundary condition near the interface, which is similar to non-slip boundary conditions in Fluid-Structure Interaction (FSI) problems. The interface is captured using a Volume of Fluid (VOF) method, and a new boundary layer is built on the lighter phase side by an immersed boundary method. The designed boundary layer helps to reduce the spurious velocity caused by the imbalance of dynamic pressure gradient and density gradient and to prevent tearing of the interface due to the tangential velocity across the interface. The influence of time step, density ratio, and spatial resolution is studied in detail for two set of cases, steady stratified flow and convection of a high-density droplet, where direct comparison is possible to potential flow analysis (i.e. infinite Reynold's number). An initial study for a droplet splashing on a thin liquid film demonstrates applicability of the new solver to real-life applications. Detailed comparisons should be performed in the future for finite Reynold's number cases to fully demonstrate the improvements in accuracy and stability of high-density ratio two-phase flow simulations offered by the new method.

Modeling High Density Ratio Incompressible Interfacial Flows

2002 ◽  
Author(s):  
Markus Bussmann ◽  
Douglas B. Kothe ◽  
James M. Sicilian
Keyword(s):  
Mass Flux ◽  
Density Ratio ◽  
Momentum Conservation ◽  
High Density ◽  
Interfacial Flows ◽  
Pressure Gradients ◽  
Careful Evaluation ◽  
Flow Equations ◽  
High Density Ratio ◽  
Consistent Approach

We present an approach to modeling incompressible interfacial flows on fixed meshes that yields solutions at any density ratio. There are two aspects of the methodology that are crucial for obtaining accurate high density ratio solutions: a consistent approach to mass and momentum conservation, by using mass flux information from an interface advection algorithm as the basis for the momentum advection calculation, and a careful evaluation of pressure gradients near the interface. Our particular implementation couples a volume tracking algorithm with a predictor/projection solution of the flow equations on unstructured meshes. We present the methodology, and then the results of several calculations.

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