Investigation of Periodic Boundary Conditions in Multipassage Cascade Flows Using Overset Grids

1999 ◽  
Vol 121 (2) ◽  
pp. 341-347 ◽  
Author(s):  
I. H. Tuncer ◽  
S. Weber ◽  
W. Sanz
Keyword(s):  
Solution Method ◽  
Grid Method ◽  
Navier Stokes ◽  
Flow Conditions ◽  
Compressor Cascade ◽  
Overset Grid ◽  
Overset Grids ◽  
Single Passage ◽  
Overset Grid Method ◽  
Background Grid

A Navier–Stokes solution method with overset grids is applied to unsteady multipassage cascade flows, and the unsteady blade loadings are compared against the single-passage solutions with the direct store interblade boundary condition. In the overset grid solutions, the multipassage domain is discretized with O-type grids around each blade and a rectangular background grid. Blade grids are allowed to move in time relative to the background grid, as prescribed by the oscillatory plunging motion. The overset grid method uses a simple, robust numerical algorithm to localize moving intergrid boundary points and to interpolate solution variables across grids. Computational results are presented for two and four-passage, subsonic and transonic flows through a turbine and a compressor cascade. The overset grid solutions over the multipassage periodic domains agree well with the single-passage solutions and the experimental data. It is concluded that the time linearization error introduced by the direct store approach is negligible in the range of flow conditions studied.

scholarly journals Investigation of Periodic Boundary Conditions in Multi-Passage Cascade Flows Using Overset Grids

1998 ◽  
Author(s):  
Ismail H. Tuncer ◽  
Stefan Weber ◽  
Wolfgang Sanz
Keyword(s):  
Solution Method ◽  
Grid Method ◽  
Navier Stokes ◽  
Flow Conditions ◽  
Compressor Cascade ◽  
Overset Grid ◽  
Overset Grids ◽  
Single Passage ◽  
Overset Grid Method ◽  
Background Grid

A Navier-Stokes solution method with overset grids is applied to unsteady multi-passage cascade flows, and the unsteady blade loadings are compared against the single passage solutions with the direct store interblade boundary condition. In the overset grid solutions, the multi-passage domain is discretized with O-type grids around each blade and a rectangular background grid. Blade grids are allowed to move in time relative to the background grid as prescribed by the oscillatory plunging motion. The overset grid method uses a simple, robust numerical algorithm to localize moving intergrid boundary points and to interpolate solution variables across grids. Computational results are presented for two and four passage, subsonic and transonic flows through a turbine and a compressor cascade. The overset grid solutions over the multi-passage periodic domains agree well with the single passage solutions and the experimental data. It is concluded that the time linearization error introduced by the direct store approach is negligible in the range of flow conditions studied.

Computation of Multi-Passage Cascade Flows With Overset and Deforming Grids

1997 ◽  
Author(s):  
Ismail H. Tuncer ◽  
Wolfgang Sanz
Keyword(s):  
Moving Boundary ◽  
Grid Method ◽  
Navier Stokes ◽  
Computational Results ◽  
Compressor Cascade ◽  
Overset Grid ◽  
Overset Grids ◽  
Overset Grid Method ◽  
Background Grid ◽  
Good Agreement

An overset grid method is applied to the solution of single and multi-passage cascade flows with a compressible Navier-Stokes solver. C-type grids around individual blades are overset onto a Cartesian background grid. Overset grids are allowed to move in time relative to each other as prescribed by the oscillatory plunging motion. The overset grid method uses a simple, robust numerical algorithm to localize moving boundary points and to interpolate solution variables across intergrid boundaries. Computational results and comparisons with single/staggered, deforming grid solutions are presented for in- and out-of-phase multi-passage flows through a compressor cascade. Very good agreement is obtained against the deforming grid solutions.

Influence Wave Mode Computations of Multi-Passage Cascade Flows

2000 ◽  
Author(s):  
Ismail H. Tuncer ◽  
Stefan Weber
Keyword(s):  
Experimental Data ◽  
Traveling Wave ◽  
Solution Method ◽  
Wave Mode ◽  
Navier Stokes ◽  
Flow Conditions ◽  
Compressor Cascade ◽  
Overset Grids ◽  
Shock Position ◽  
Flow Domain

A Navier-Stokes solution method with overset grids is employed to compute the Influence Wave Modes of a compressor cascade in transonic flow conditions. The computed predictions are compared against the experimental data and the predictions based on Traveling Wave Mode computations performed using a different Navier-Stokes solver. In the present method, a five-passage flow domain is discretized with O-type subgrids around each blade and a rectangular background subgrid. A simple, robust numerical algorithm is used to localize moving intergrid boundary points, and to interpolate solution variables across the subgrids. The influence wave mode computation predicts a strong influence of the pitching mid-blade on the shock position of the neighboring blades. The predictions agree with the experimental data fairly well, and shows an improvement over the Traveling Wave Mode predictions.

Introduction of Combined Usage of Overset Grid Method in Conjugate Heat Transfer Simulation

2009 ◽  
Author(s):  
Takashi Yamane ◽  
Kazuomi Yamamoto
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Conjugate Heat Transfer ◽  
Grid Method ◽  
Grid Generation ◽  
Computational Grids ◽  
Overset Grid ◽  
Overset Grid Method ◽  
Background Grid ◽  
Heat Transfer Simulation

The conjugate heat transfer simulation is expected to simulate precise temperature distributions of turbine cooling structures and contribute to the reduction of cooling air usage. However, the generation of computational grids for highly complicated cooling structures in turbine blade is a quite difficult work, especially in the conjugate simulation because grids for fluid and solid regions should be generated simultaneously. In this study the combined usage of the overset grid method with the attached multiblock grid method is introduced for the grid generation with less effort. In the original UPACS flow solver, the overset is treated as one type of boundary conditions where the data are interpolated from the background grid blocks. If the interpolations of data are allowed along the solid surface which is the connecting boundary of fluid and solid grid blocks, the heat flux calculation becomes quite complicated and the benefits of longstanding researches on the turbulence models for boundary fitted grids cannot be used, thus the overset treatments have been limited among the same type of calculation blocks, that is, the fluid blocks should be on the background grid of fluid region and the solid blocks should be on the background grid of solid region. The procedure to create grids with the above restriction has also developed. Numerical result using the overset grid method is compared with the conventional multi-block grid result for evaluation. With this method, the grid generation labor for such as parametric simulations of different arrangements of film holes in a turbine blade will be greatly reduced.

Numerical simulation of an X-wing flapping wing MAV by means of a deforming overset grid method

2015 ◽  
Author(s):  
Shuanghou Deng ◽  
Tianhang Xiao ◽  
Mustafa Percin ◽  
Bas van Oudheusden ◽  
Hester Bijl ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Grid Method ◽  
Flapping Wing ◽  
Overset Grid ◽  
Overset Grid Method

Prediction of Slamming Loads on Catamaran Wetdeck Using CFD

2015 ◽  
Author(s):  
Ahmed Swidan ◽  
Giles Thomas ◽  
Dev Ranmuthugala ◽  
Irene Penesis ◽  
Walid Amin ◽  
...  
Keyword(s):  
Model Simulation ◽  
Three Dimensional ◽  
Grid Method ◽  
Computationally Efficient ◽  
Overset Grid ◽  
Force Magnitude ◽  
Overset Grid Method ◽  
Drop Tests ◽  
Transient Velocity ◽  
Transient Velocity Profile

Wetdeck slamming is one of the principal hydrodynamic loads acting on catamarans. CFD techniques are shown to successfully characterise wetdeck slamming loads, as validated through a series of controlled-speed drop tests on a three-dimensional catamaran hullform model. Simulation of water entry at constant speed by applying a fixed grid method was found to be more computationally efficient than applying an overset grid. However, the overset grid method for implementing the exact transient velocity profile resulted in better prediction of slam force magnitude. In addition the splitting force concurrent with wetdeck slam event was quantified to be 21% of the vertical slamming force.

An overset grid method for large eddy simulation of turbomachinery stages

2014 ◽  
Vol 274 ◽  
pp. 333-355 ◽  
Author(s):  
Gaofeng Wang ◽  
Florent Duchaine ◽  
Dimitrios Papadogiannis ◽  
Ignacio Duran ◽  
Stéphane Moreau ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Grid Method ◽  
Overset Grid ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Overset Grid Method

Simulation of Working Posture of Deepwater Gravity Sampling Device Using OpenFOAM

2018 ◽  
Author(s):  
Zhe Ma ◽  
Danya Kong ◽  
Yin Wang ◽  
Nianxin Ren ◽  
Gangjun Zhai
Keyword(s):  
Sampling Rate ◽  
Grid Method ◽  
Sampling Device ◽  
Overset Grids ◽  
Working Posture ◽  
Overset Grid Method ◽  
Computational Fluid Dynamics Cfd ◽  
Marine Engineering ◽  
Free Falling ◽  
The Relationship

Computational fluid dynamics (CFD) has been widely used in the field of marine engineering recent years. In this work, the free falling process and working posture of gravity sampler have been studied using OpenFOAM. The overset grids have been used to simulate the movement of the sampler in the flow field. Main works are as follows: (1) verifying the accuracy of the overset grid method; (2) establishing a numerical model using the Newmark method to analyze the responses of sampler vertical and slant drop; (3) investigating the relationship among the deflection angle, falling speed and sampling rate of sampler. Finally, the best fall distance of GPS-01 sampler has been recommended in combination with the falling velocity and the initial falling angle.

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