A finite-difference summation-by-parts, conditionally stable partitioned algorithm for conjugate heat transfer problems
Sarah Nataj, David C. Del Rey Fernández, David Brown, Rajeev Jaiman
TL;DR
This work develops a high-order finite-difference partitioned solver for conjugate heat transfer problems by integrating summation-by-parts (SBP) operators with simultaneous approximation terms (SATs) on curvilinear grids. The left and right subdomains solve fluid-like and solid-like equations, respectively, and exchange interface data through carefully designed SAT penalties to yield provable conditional energy stability under a CFL-like time-step constraint and parameter choices. The authors extend the 1D SBP–SAT stability analysis to 3D curvilinear geometries, introduce time-extrapolation-based interface initial guesses (EXT) to improve accuracy, and demonstrate numerical verification with manufactured solutions, highlighting spatial convergence and interface behavior. The approach enables truly modular solvers for multi-physics problems on complex geometries while maintaining energy stability and high-order accuracy, with potential extensions to non-conforming meshes and more realistic turbulent transfer scenarios.
Abstract
In this work, we design and analyze a novel, provably conditionally stable, weakly coupled partitioned scheme to solve the conjugate heat transfer (CHT) problem. We consider a model CHT problem consisting of linear advection-diffusion and heat equations, coupled at an interface through continuity of temperature and heat flux. We employ high-order summation-by-parts finite-difference operators in conjunction with simultaneous-approximation-terms (SATs) in curvilinear coordinates for spatial derivatives, combined with first- and second-order time discretizations and temporal extrapolation at the interface. Energy stability is maintained by carefully selecting SAT parameters at the interface. A range of coupling parameters are explored to identify those that yield a stable scheme, and a stepwise approach for choosing SAT parameters that ensure stability is given. The effectiveness of the method is demonstrated through numerical experiments in a two-dimensional model problem on a rectangular domain with curvilinear grids. The proposed approach enables the development of high-order, conditionally stable partitioned solvers suitable for general geometries.
