Numerical Simulation of the Two-Dimensional Viscous Compressible Flow in Blade Cascades Using a Solution-Adaptive Unstructured Mesh

1990 ◽  
Vol 112 (3) ◽  
pp. 311-319 ◽  
Author(s):  
G. L. D. Side´n ◽  
W. N. Dawes ◽  
P. J. Albra˚ten
Keyword(s):  
Compressible Flows ◽  
Stokes Equations ◽  
Rapid Development ◽  
Automatic Generation ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Explicit Finite Element ◽  
Eddy Viscosity Model ◽  
Viscous Compressible Flow

An explicit finite element procedure has been coupled with an automatic generation procedure for mesh-adaptive steady-state simulations of two-dimensional viscous compressible flows in cascades. Turbulence is modeled by a two-layer algebraic eddy viscosity model. Results show good behavior in comparison with measurements and results of a conventional H-mesh viscous flow solver. Computed loss approaches measured loss as the mesh is refined. Currently, the unstructured solver suffers in efficiency terms because the automatic mesh generator tends to produce inefficient equilateral triangles in the regions of shock waves and boundary layers where stretched elements would be more appropriate. This means that, at least for the Navier–Stokes equations, the unstructured approach is not yet competitive with conventional structured techniques. Nevertheless, this will change once the key advantages of geometric flexibility and user-independent solutions force rapid development.

scholarly journals Numerical Simulation of the Two Dimensional Viscous Compressible Flow in Blade Cascades Using a Solution Adaptive Unstructured Mesh

1989 ◽  
Author(s):  
Gunnar L. D. Sidén ◽  
William N. Dawes ◽  
Per J. Albråten
Keyword(s):  
Compressible Flows ◽  
Stokes Equations ◽  
Rapid Development ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Explicit Finite Element ◽  
Eddy Viscosity Model ◽  
Viscous Compressible Flow ◽  
Automatic Mesh

An explicit finite element procedure has been coupled with an automatic mesh generation procedure for mesh adaptive steady state simulations of two-dimensional viscous compressible flows in cascades. Turbulence is modelled by a two-layer algebraic eddy viscosity model. Results show good behavior in comparison with measurements and results of a conventional H-mesh viscous flow solver. Computed loss approaches measured loss as the mesh is refined. Currently, the unstructured solver suffers in efficiency terms because the automatic mesh generator tends to produce inefficient equilateral triangles in the regions of shock waves and boundary layers where stretched elements would be more appropriate. This means that, at least for the Navier-Stokes equations, the unstructured approach is not yet competitive with conventional structured techniques. Nevertheless, this will change once the key advantages of geometric flexibility and user independent solutions force rapid development.

scholarly journals Turbulent flow on a planar moving belt and a rotating disk: modelling and comparisons

2007 ◽  
Vol 587 ◽  
pp. 255-270 ◽  
Author(s):  
JOHN M. McDARBY ◽  
FRANK T. SMITH
Keyword(s):  
Turbulent Flow ◽  
Stokes Equations ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Eddy Viscosity Model ◽  
High Reynolds ◽  
Carry Over

Modelling of the fully turbulent flow produced on a moving belt and of that induced ona rotating disk is described, for each of which a more analytical approach is adopted than previously seen. The analysis for the two-dimensional moving belt indicates novel structures and these are found to carry over directly to the rotating disk flow which, ignoring the transitional regime, is three-componential but two-dimensional due to axisymmetry. This is based on addressing the Reynolds-averaged Navier–Stokes equations together with an eddy viscosity model, with the flow structure being analysed for high Reynolds numbers. A classical (von Kármán) constant within the model plays an important and surprising role, indicating that each of the belt and the disk flows has quite a massive thickness. Comparisons made with previous work show varying degrees of agreement. The approach, including the new prediction of massive thicknesses independent of the Reynoldsnumber, is expected to extend to flows induced by rotary blades, by related rotary devices and by other configurations of industrial interest.

Direct simulation of transition in an oscillatory boundary layer

1998 ◽  
Vol 371 ◽  
pp. 207-232 ◽  
Author(s):  
G. VITTORI ◽  
R. VERZICCO
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Turbulent Regime ◽  
Two Dimensional ◽  
Temporal Development ◽  
Direct Simulation ◽  
Navier Stokes Equations ◽  
Oscillatory Boundary Layer

Numerical simulations of Navier–Stokes equations are performed to study the flow originated by an oscillating pressure gradient close to a wall characterized by small imperfections. The scenario of transition from the laminar to the turbulent regime is investigated and the results are interpreted in the light of existing analytical theories. The ‘disturbed-laminar’ and the ‘intermittently turbulent’ regimes detected experimentally are reproduced by the present simulations. Moreover it is found that imperfections of the wall are of fundamental importance in causing the growth of two-dimensional disturbances which in turn trigger turbulence in the Stokes boundary layer. Finally, in the intermittently turbulent regime, a description is given of the temporal development of turbulence characteristics.

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