Gambit and Fluent: Turbulent Flow and Heat Transfer in a Mixing Elbow

Gambit and Fluent: Turbulent Flow and Heat Transfer in a Mixing Elbow 1.Abstract This exercise comprises of two sections A and B, where in the first section an analysis in creating initial vertices will be carried out along with the creation of edges and faces, and the setting of boundary types. The program used for this phase of the investigation will be Gambit. These will then be generated into a mesh using Fluent. Moreover, section B will focus on the sensitivity to the computational mesh, sensitivity to the residuals and the use of higher order numerical discretization schemes. The structure of this report analyses the discretization of meshes, showing difference in results subject to variable changes. The general findings show that the different contours and iterations produced become increasingly accurate as the grid value increase or the order of discretization increases. 2. Altering the Residuals The following graphs show comparisons in residuals for different number of iterations, for a first order discretization 2.1 Iteration for a triangular mesh {draw:frame} {draw:frame} Figure 2.1: Original mesh Figure 2.2:Mesh with reduced residuals 2.2 Iteration for a quadilateral mesh {draw:frame} {draw:frame} Figure 2.3: Original mesh Figure 2.4: Mesh with reduced residuals From the graphs above one can observe an increase in iteration when the residuals are reduced. However, the general shape of the curves remain exactly the same for both the triangular and quadrilateral mesh. From these findings it can be concluded that as the convergent rate decreases, the number of iterations becomes more important. When the convergence was set at a value less than 10e-04 the results were more accurate. *3. Comparison For* First Order Discretization 3.1 Velocity magnitude {draw:frame} {draw:frame} Figure 3.1: Velocity variation for triangular mesh Figure 3.2: Velocity Variation for quadrilateral mesh These graphs show that the

References: Tutorial 1. Turbulent Flow and Heat Transfer in a mixing Transfer in a Mixing Elbow. Dr. Mark Cotton