Development and assessment of adjoint sensitivity analysis method for transient two-phase flow simulations

Research output: Contribution to conferencePaper

Abstract

The adjoint method is efficient for calculating sensitivities of few responses to a large number of parameters. The cost of solving an adjoint equation is comparable to the cost of solving the forward governing equation. Once the adjoint solution is available, the sensitivities to any number of parameters can be calculated with little effort. There are two methods to develop the adjoint equations: continuous method and discrete method. In the continuous method, the control theory is applied to the forward governing equation and produces an analytical partial differential equation for solving the adjoint variable; in the discrete method, the control theory is applied to the discrete form of the forward governing equation and produces a linear system of equations for solving the adjoint variable. In this article, an adjoint sensitivity analysis framework is developed using both the continuous and discrete methods. These two methods are assessed with one transient test case. Adjoint sensitivities from both methods are verified by sensitivities calculated with a perturbation method. Adjoint sensitivities from both methods are physically reasonable and match each other. The sensitivities obtained with discrete method is found to be more accurate than the sensitivities from the continuous method. Though continuous method is computationally more efficient than the discrete method, difficulties are observed in solving the continuous adjoint equation for cases where the adjoint equation contains sharp discontinuities in the source terms. In such cases, the continuous method is not as robust as the discrete adjoint method.

Original languageEnglish (US)
Pages2246-2259
Number of pages14
StatePublished - Jan 1 2019
Event18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019 - Portland, United States
Duration: Aug 18 2019Aug 23 2019

Conference

Conference18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019
CountryUnited States
CityPortland
Period8/18/198/23/19

Keywords

  • Adjoint method
  • Sensitivity analysis
  • Transient two-phase flow

ASJC Scopus subject areas

  • Nuclear Energy and Engineering
  • Instrumentation

Fingerprint Dive into the research topics of 'Development and assessment of adjoint sensitivity analysis method for transient two-phase flow simulations'. Together they form a unique fingerprint.

  • Cite this

    Hu, G., & Kozlowski, T. (2019). Development and assessment of adjoint sensitivity analysis method for transient two-phase flow simulations. 2246-2259. Paper presented at 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019, Portland, United States.