Verification of a Multiphysics Code with Method of Manufactured Solutions

To push the modeling and simulation to a new level in simulating realistic problems, a common practice is to couple different single-physics codes together to simulate problems involving multiple physics. Although the method of manufactured solutions (MMS) has been shown to be a powerful tool in code verification, there has been little work on applying MMS to a multi-physics code system. Additionally, due to the scarcity of multi-physics validation data, the significance of code verification becomes more prominent as an important part in software quality assurance. With this, the application of MMS to a coupled code system, e.g. VERA-CS, has become a crucial step, which helps identify bugs affecting the order of accuracy, thus increasing the credibility and reliability of the code. In this work, we investigate the application of MMS to verify a multi-physics code system and establish a framework for this application, and we demonstrate this with a neutronics code coupled with a thermal hydraulics (TH) code. The convection module is not yet added to this work, so by TH, only conduction is considered