An Investigation into the Convergence of the AF-CGS method. G.U. Aero Report 9327

The relationship between the relative residual produced by the AFCGS method and the lift, drag and pressure coefficients is investigated for steady turbulent flow over a NACA64A010 aerofoil, and over an RAE2822 aerofoil. This enables the most suitable convergence criterion to be established

An Investigation into the Convergence of the AF-CGS method. G.U. Aero Report 9327

The relationship between the relative residual produced by the AFCGS method and the lift, drag and pressure coefficients is investigated for steady turbulent flow over a NACA64A010 aerofoil, and over an RAE2822 aerofoil. This enables the most suitable convergence criterion to be established

An Investigation of Mesh Sequencing and Mesh Coarsening for the AF-CGS method. G.U. Aero Report 9411

The use of mesh sequencing as a way to speed up the convergence of the AF-CGS method is considered for the AGARD test case 9. A mesh refinement study is also carried out to determine a compromise mesh which will produce an accurate solution with fewer grid points

An Investigation of Mesh Sequencing and Mesh Coarsening for the AF-CGS method. G.U. Aero Report 9411

The use of mesh sequencing as a way to speed up the convergence of the AF-CGS method is considered for the AGARD test case 9. A mesh refinement study is also carried out to determine a compromise mesh which will produce an accurate solution with fewer grid points

Time Stepping Approaches for Three-Dimensional Transonic Viscous Flows. G.U. Aero Report 9412

A novel time-stepping approach is presented for the three-dimensional thin-layer Navier-Stokes equations. The method involves a two factor approximate factorisation and uses a preconditioned conjugate gradient solution for one of the factors. The method has potential to provide most of the advantages of a fully unfactored method without the huge memory requirements. A partially implicit method is also considered. Results and a stability analysis are presented to evaluate the approaches

Fast and Accurate Unfactored Two-Dimensional Turbulent Flow Simulation. G.U. Aero Report 9326

The approximate factorisation-conjugate gradient squared (AF-CGS) method has been successfully demonstrated for unsteady turbulent flows. In the present paper the method is adapted to obtain rapid convergence for steady flows. Modifications to the original method are described and test results are given for a laminar subsonic flow and two turbulent supersonic flows including the well studied AGARD RAE2822 case 9

Galaxy Clusters Associated with Short GRBs. II. Predictions for the Rate of Short GRBs in Field and Cluster Early-Type Galaxies

We determine the relative rates of short GRBs in cluster and field early-type galaxies as a function of the age probability distribution of their progenitors, P(\tau) \propto \tau^n. This analysis takes advantage of the difference in the growth of stellar mass in clusters and in the field, which arises from the combined effects of the galaxy stellar mass function, the early-type fraction, and the dependence of star formation history on mass and environment. This approach complements the use of the early- to late-type host galaxy ratio, with the added benefit that the star formation histories of early-type galaxies are simpler than those of late-type galaxies, and any systematic differences between progenitors in early- and late-type galaxies are removed. We find that the ratio varies from R(cluster)/R(field) ~ 0.5 for n = -2 to ~ 3 for n = 2. Current observations indicate a ratio of about 2, corresponding to n ~ 0 - 1. This is similar to the value inferred from the ratio of short GRBs in early- and late-type hosts, but it differs from the value of n ~ -1 for NS binaries in the Milky Way. We stress that this general approach can be easily modified with improved knowledge of the effects of environment and mass on the build-up of stellar mass, as well as the effect of globular clusters on the short GRB rate. It can also be used to assess the age distribution of Type Ia supernova progenitors.Comment: ApJ accepted versio

Some convergence enhancing schemes for systems of conservation laws

SIGLEAvailable from British Library Document Supply Centre- DSC:D177797 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Some convergence enhancing schemes for systems of conservation laws

SIGLEAvailable from British Library Document Supply Centre- DSC:D177797 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Fast and Accurate Unfactored Two-Dimensional Turbulent Flow Simulation. G.U. Aero Report 9326

The approximate factorisation-conjugate gradient squared (AF-CGS) method has been successfully demonstrated for unsteady turbulent flows. In the present paper the method is adapted to obtain rapid convergence for steady flows. Modifications to the original method are described and test results are given for a laminar subsonic flow and two turbulent supersonic flows including the well studied AGARD RAE2822 case 9