Error estimate of Gauge–Uzawa methods for incompressible flows with variable density

2020 ◽  
Vol 364 ◽  
pp. 112321 ◽  
Author(s):  
Hongtao Chen ◽  
Jingjing Mao ◽  
Jie Shen
Keyword(s):  
Error Estimate ◽  
Incompressible Flows ◽  
Variable Density ◽  
Uzawa Methods

scholarly journals A numerical study of a variable-density low-speed turbulent mixing layer

2017 ◽  
Vol 830 ◽  
pp. 569-601 ◽  
Author(s):  
Antonio Almagro ◽  
Manuel García-Villalba ◽  
Oscar Flores
Keyword(s):  
Growth Rate ◽  
Mach Number ◽  
Incompressible Flows ◽  
Numerical Study ◽  
Density Ratio ◽  
Mixing Layer ◽  
Variable Density ◽  
The Self ◽  
Low Speed ◽  
Self Similar

Direct numerical simulations of a temporally developing, low-speed, variable-density, turbulent, plane mixing layer are performed. The Navier–Stokes equations in the low-Mach-number approximation are solved using a novel algorithm based on an extended version of the velocity–vorticity formulation used by Kim et al. (J. Fluid Mech., vol 177, 1987, 133–166) for incompressible flows. Four cases with density ratios $s=1,2,4$ and 8 are considered. The simulations are run with a Prandtl number of 0.7, and achieve a $Re_{\unicode[STIX]{x1D706}}$ up to 150 during the self-similar evolution of the mixing layer. It is found that the growth rate of the mixing layer decreases with increasing density ratio, in agreement with theoretical models of this phenomenon. Comparison with high-speed data shows that the reduction of the growth rates with increasing density ratio has a weak dependence with the Mach number. In addition, the shifting of the mixing layer to the low-density stream has been characterized by analysing one-point statistics within the self-similar interval. This shifting has been quantified, and related to the growth rate of the mixing layer under the assumption that the shape of the mean velocity and density profiles do not change with the density ratio. This leads to a predictive model for the reduction of the growth rate of the momentum thickness, which agrees reasonably well with the available data. Finally, the effect of the density ratio on the turbulent structure has been analysed using flow visualizations and spectra. It is found that with increasing density ratio the longest scales in the high-density side are gradually inhibited. A gradual reduction of the energy in small scales with increasing density ratio is also observed.

An Algorithm for Variable Density Flows

2007 ◽  
Author(s):  
S. Rahul ◽  
Vinayak Eswaran ◽  
P. Shyam Sundar
Keyword(s):  
Helmholtz Equation ◽  
Poisson Equation ◽  
Finite Volume ◽  
Turbulent Combustion ◽  
Incompressible Flows ◽  
Variable Density ◽  
Fluid Mixing ◽  
Structured Grid ◽  
Fully Implicit ◽  
Implicit Solver

An algorithm for solving variable density incompressible flows is presented. This algorithm is implemented on a finite volume based fully implicit solver employing a non-staggered hexahedral structured grid arrangement. Momentum interpolation is used for pressure-velocity coupling and the resulting Poisson equation for pressure is modified to a Helmholtz equation for better convergence. This algorithm is used for solving problems involving the variation of density due to temperature, fluid mixing and turbulent combustion flows.

A new fractional time-stepping method for variable density incompressible flows

2013 ◽  
Vol 242 ◽  
pp. 124-137 ◽  
Author(s):  
Ying Li ◽  
Liquan Mei ◽  
Jiatai Ge ◽  
Feng Shi
Keyword(s):  
Incompressible Flows ◽  
Variable Density ◽  
Time Stepping
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