Effect of Forward Sweep on the Performance of an Axial Blower

Effects of changing the blade sweep without redesigning the datum blade sections are studied on the pressure rise, efficiency and 3D flow field of an axial blower. Four forward swept blade configurations (5°, 10°, 15° and 20°) are compared with an unswept blade. RANS and URANS simulations are carried out for the aerodynamic performance analysis and 3D flow field behaviour. Results indicated higher pressure rise and wider stall margin thus improved efficiency with higher forward sweep angles

FUN3D Manual: 13.2

This manual describes the installation and execution of FUN3D version 13.2, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status

FUN3D Manual: 13.3

This manual describes the installation and execution of FUN3D version 13.3, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status

FUN3D Manual: 13.5

This manual describes the installation and execution of FUN3D (Fully-UNstructured three-dimensional CFD (Computational Fluid Dynamics) code) version 13.5, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status

Experimental Investigations on the Role of Structure in Turbulent Mixing of Initially Isolated Scalars

Structured stirring and mixing play a dominate role in turbulent mixing and are important processes across a wide range of applications. The mixing of two scalars that share an interface has the same topology of a single scalar problem, and therefore has dominated the literature. The mixing of two scalars separated by a third, ambient fluid has received much less attention. This topology is of particular interest in that stirring may not always increase mixing between the two scalars, and some stirring protocols may further segregate the two scalars. This topology is common in many biological, environmental, chemical, industrial, and scientific applications.The present thesis begins by developing an experimental framework with which two scalars separated by a third ambient fluid can be studied. The technique presented, referred to herein as two-channel PLIF, simultaneously quantifies two scalar fields using a pair of independently operated single-color PLIF systems that synchronously image a common region.The two-channel technique is used to investigate how stirring and mixing bring together initially isolated scalars in a variety of flows. Flows examined include laminar vortex shedding in the cylinder wake, plumes in grid turbulence, and low Reynolds number parallel turbulent jets. It is found that the turbulence properties and flow geometry are important in determining the effect of instantaneous processes. When the separation distance of the scalars is small compared to the largest turbulence length-scales, instantaneous mixing processes are responsible for over 80% of the coalescence between the two. Further analysis using joint probabilities of the two scalars indicates that turbulent structure brings scalar filaments near to each other in attracting regions of the flow before diffusive flux brings the two scalars into coalescence. This is the first study to show in a variety of flows that turbulent structure imparts spatial correlations on initially distant scalars

Resolution of Tip Vortices by grid-based, grid-free and coupled methods using CFD

The vortex structure resolution is one of the vital problems of CFD as inherent artificial dissipation effects lead to an unphysical strong decay of the vortices. The overall objective of this work is to improve the resolution of concentrated vortices. This work focuses on grid based, grid free methods and coupled methods to capture the details of vortices especially further downstream after the vortex has rolled up and started to decay. The work focuses on a hybrid method as a coupling of grid based and grid free vortex method

Numerical Simulation of a Marine Current Turbine in Turbulent Flow

The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the authorThe marine current turbine (MCT) is an exciting proposition for the extraction of renewable tidal and marine current power. However, the numerical prediction of the performance of the MCT is difficult due to its complex geometry, the surrounding turbulent flow and the free surface. The main purpose of this research is to develop a computational tool for the simulation of a MCT in turbulent flow and in this thesis, the author has modified a 3D Large Eddy Simulation (LES) numerical code to simulate a three blade MCT under a variety of operating conditions based on the Immersed Boundary Method (IBM) and the Conservative Level Set Method (CLS). The interaction between the solid structure and surrounding fluid is modelled by the immersed boundary method, which the author modified to handle the complex geometrical conditions. The conservative free surface (CLS) scheme was implemented in the original Cgles code to capture the free surface effect. A series of simulations of turbulent flow in an open channel with different slope conditions were conducted using the modified free surface code. Supercritical flow with Froude number up to 1.94 was simulated and a decrease of the integral constant in the law of the wall has been noticed which matches well with the experimental data. Further simulations of the marine current turbine in turbulent flow have been carried out for different operating conditions and good match with experimental data was observed for all flow conditions. The effect of waves on the performance of the turbine was also investigated and it has been noticed that this existence will increase the power performance of the turbine due to the increase of free stream velocity