A Compressible High-Order Unstructured Spectral Difference Code for Stratified Convection in Rotating Spherical Shells

TL;DR

The paper introduces CHORUS, a high-order spectral difference code for simulating stratified convection in rotating spherical shells, demonstrating high parallel efficiency and accurate results comparable to established benchmarks.

Contribution

The novel CHORUS code employs a high-order spectral difference method on unstructured meshes for efficient, scalable simulations of stellar and planetary interior convection.

Findings

Excellent parallel performance up to 12,000 cores

Good agreement with benchmark results for Jupiter and Sun convection

Enables simulations of multi-scale and rapidly-rotating stellar phenomena

Abstract

We present a novel and powerful Compressible High-ORder Unstructured Spectral-difference (CHORUS) code for simulating thermal convection and related fluid dynamics in the interiors of stars and planets. The computational geometries are treated as rotating spherical shells filled with stratified gas. The hydrodynamic equations are discretized by a robust and efficient high-order Spectral Difference Method (SDM) on unstructured meshes. The computational stencil of the spectral difference method is compact and advantageous for parallel processing. CHORUS demonstrates excellent parallel performance for all test cases reported in this paper, scaling up to 12,000 cores on the Yellowstone High-Performance Computing cluster at NCAR. The code is verified by defining two benchmark cases for global convection in Jupiter and the Sun. CHORUS results are compared with results from the ASH code and good agreement is found. The CHORUS code creates new opportunities for simulating such varied phenomena as multi-scale solar convection, core convection, and convection in rapidly-rotating, oblate stars.