Staggered grid
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(It's used for simulations of compressible flows too) |
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| - | On a staggered grid the scalar variables (pressure, density, total enthalpy etc.) are stored in the cell centers of the control volumes, whereas the velocity or momentum variables are located at the cell faces. This is different from a [[Collocated grid|collocated grid]] arrangement, where all variables are stored in the same positions. A staggered storage is mainly used on [[Mesh_classification#Structured_Meshes|structured grids]] for [[Incompressible flow|incompressible flow]] simulations. | + | On a staggered grid the scalar variables (pressure, density, total enthalpy etc.) are stored in the cell centers of the control volumes, whereas the velocity or momentum variables are located at the cell faces. This is different from a [[Collocated grid|collocated grid]] arrangement, where all variables are stored in the same positions. A staggered storage is mainly used on [[Mesh_classification#Structured_Meshes|structured grids]] for [[Compressible flow|compressible]] or [[Incompressible flow|incompressible flow]] simulations. |
Using a staggered grid is a simple way to avoid [[Odd-even decoupling|odd-even decoupling]] between the pressure and velocity. Odd-even decoupling is a discretization error that can occur on collocated grids and which leads to checkerboard patterns in the solutions. | Using a staggered grid is a simple way to avoid [[Odd-even decoupling|odd-even decoupling]] between the pressure and velocity. Odd-even decoupling is a discretization error that can occur on collocated grids and which leads to checkerboard patterns in the solutions. | ||
Latest revision as of 16:17, 3 March 2012
On a staggered grid the scalar variables (pressure, density, total enthalpy etc.) are stored in the cell centers of the control volumes, whereas the velocity or momentum variables are located at the cell faces. This is different from a collocated grid arrangement, where all variables are stored in the same positions. A staggered storage is mainly used on structured grids for compressible or incompressible flow simulations.
Using a staggered grid is a simple way to avoid odd-even decoupling between the pressure and velocity. Odd-even decoupling is a discretization error that can occur on collocated grids and which leads to checkerboard patterns in the solutions.
The disadvantage of using staggered grids is that different variable are stored at different places and this makes it more difficult to handle different control volumes for different varibales and to keep track of the metrics. Most modern codes instead use a collocated storage.
References
Harlow, F. H. and Welch, J. E. (1965), "Numerical calculation of time-dependent viscous incompressible flow of fluid with free surface", Phys. Fluids. 8, 2182.
