Pei Hung Lin

HYDRODYNAMIC SIMULATIONS OF H ENTRAINMENT AT THE TOP OF He-SHELL FLASH CONVECTION

We present the first 3-dimensional, fully compressible gas-dynamics simulations in

Moving Scientific Codes to Multicore Microprocessor CPUs

4\pi

Revisiting loop fusion in the polyhedral framework

geometry of He-shell flash convection with proton-rich fuel entrainment at the upper boundary. This work is motivated by the insufficiently understood observed consequences of the H-ingestion flash in post-AGB stars (Sakurais object) and metal-poor AGB stars. Our investigation is focused on the entrainment process at the top convection boundary and on the subsequent advection of H-rich material into deeper layers, and we therefore ignore the burning of the proton-rich fuel in this study. We find that, for our deep convection zone, coherent convective motions of near global scale appear to dominate the flow. At the top boundary convective shear flows are stable against Kelvin-Helmholtz instabilities. However, such shear instabilities are induced by the boundary-layer separation in large-scale, opposing flows. This links the global nature of thick shell convection with the entrainment process. We establish the quantitative dependence of the entrainment rate on grid resolution. With our numerical technique simulations with

Scaling the Multifluid PPM Code on Blue Waters and Intel MIC

1024^3

A Study of Performance Portability Using Piecewise-Parabolic Method (PPM) Gas Dynamics Applications

cells or more are required to reach a numerical fidelity appropriate for this problem. However, only the result from the

A Study of the Performance of Multifluid PPM Gas Dynamics on CPUs and GPUs

1536^3

Transforming the multifluid PPM algorithm to run on GPUs

simulation provides a clear indication that we approach convergence with regard to the entrainment rate. Our results demonstrate that our method, which is described in detail, can provide quantitative results related to entrainment and convective boundary mixing in deep stellar interior environments with veryvstiff convective boundaries. For the representative case we study in detail, we find an entrainment rate of

GLOBAL NON-SPHERICAL OSCILLATIONS IN THREE-DIMENSIONAL 4π SIMULATIONS OF THE H-INGESTION FLASH

4.38 \pm 1.48 \times 10^{-13}M_\odot \mathrm{/s}

First experience of compressible gas dynamics simulation on the Los Alamos roadrunner machine

.

CFD Builder: A Library Builder for Computational Fluid Dynamics

The IBM Cell processor represents the first and most extreme of a new generation of multicore CPUs. For scientific codes that can be formulated in terms of vector computing concepts, as far as we know, the Cell is the most rewarding. In this article, we present a method for implementing numerical algorithms for scientific computing so that they run efficiently on the Cell processor and other multicore CPUs. We present our method using the piecewise-parabolic method (PPM) gas dynamics algorithm but believe that many other algorithms could benefit from our approach. Nevertheless, the code transformations are difficult to perform manually, so we are undertaking an effort to build simplified tools to assist in at least the most tedious of the code transformations involved.