Grid classification

Grid or Mesh is defined as smaller shapes formed after discretisation of geometric domain. Mesh or Grid can be in 3- dimension and 2-dimension. Meshing has applications in fields of Geography, designing, CFD (Computational Fluid Dynamics). and many more places. The 2-dimensional meshing includes simple polygon, polygon with holes, multiple domain and curved domain. In 3 dimensions there are three types of inputs. They are simple polyhedron, geometrical polyhedron and multiple polyhedrons. Before defining the mesh type it is necessary to understand elements (their shape and size). Grid or Mesh is defined as smaller shapes formed after discretisation of geometric domain. Mesh or Grid can be in 3- dimension and 2-dimension. Meshing has applications in fields of Geography, designing, CFD (Computational Fluid Dynamics). and many more places. The 2-dimensional meshing includes simple polygon, polygon with holes, multiple domain and curved domain. In 3 dimensions there are three types of inputs. They are simple polyhedron, geometrical polyhedron and multiple polyhedrons. Before defining the mesh type it is necessary to understand elements (their shape and size). The shape of the elements is of great importance in solving the CFD problems. They are typically based on aspect ratio i.e. the aspect ratio of element decide whether a particular element would be good to use or we should go for another element with different aspect ratio. For example, if the aspect ratio is large the speed of solver reduces while if this ratio is small the solver speed increases. Large aspect ratio has another limitation of leading to interpolation errors. But if the results vary with direction then we use large aspect ratio. Most of the fluid flow equations are easily solved by discretizing procedures using the Cartesian coordinate system. In this system the implementation of finite volume method is simpler and easier to understand. But most of the engineering problems deal with complex geometries that don’t work well in the Cartesian coordinate system. When the boundary region of the flow doesn’t coincide with the coordinate lines of the structured grid then we can solve the problem by geometry approximation. Figure 1a. and 1b. shows how a cylinder can be approximated with the Cartesian coordinate system.