TY - JOUR
T1 - Adjoint-based optimization of a source-term representation of vortex generators
AU - Florentie, Liesbeth
AU - Hulshoff, Steven
AU - van Zuijlen, Alexander
PY - 2017/12/16
Y1 - 2017/12/16
N2 - An optimization approach is presented that can be used to find the optimal source term distribution in order to represent a high-fidelity vortex-generator (VG) induced flow field on a coarse mesh. The ap- proach employs the continuous adjoint of the problem, from which an exact sensitivity is calculated and used in combination with a trust-region method to find the source term which minimizes the deviation with respect to the reference velocity field. The algorithm is applied to an incompressible flow over a rectangular VG and VG pair on a flat plate and compared to results obtained with the jBAY-model and a body-fitted mesh simulation. The results indicate that a highly accurate flow, yielding only minimal errors with respect to the shape factor, circulation and vortex core, can be obtained on coarse meshes when adding a source term to only a limited number of cells. This approach therefore demonstrates the potential of source-term models to include the effects of VGs in computations of large-scale geometries. It also allows quantification of the achievable accuracy on a particular mesh and the calculation of the source term which is optimal for a specific situation. Furthermore, the optimization approach can be used to diagnose the deficiencies of an existing source-term VG model, in this work the jBAY model.
AB - An optimization approach is presented that can be used to find the optimal source term distribution in order to represent a high-fidelity vortex-generator (VG) induced flow field on a coarse mesh. The ap- proach employs the continuous adjoint of the problem, from which an exact sensitivity is calculated and used in combination with a trust-region method to find the source term which minimizes the deviation with respect to the reference velocity field. The algorithm is applied to an incompressible flow over a rectangular VG and VG pair on a flat plate and compared to results obtained with the jBAY-model and a body-fitted mesh simulation. The results indicate that a highly accurate flow, yielding only minimal errors with respect to the shape factor, circulation and vortex core, can be obtained on coarse meshes when adding a source term to only a limited number of cells. This approach therefore demonstrates the potential of source-term models to include the effects of VGs in computations of large-scale geometries. It also allows quantification of the achievable accuracy on a particular mesh and the calculation of the source term which is optimal for a specific situation. Furthermore, the optimization approach can be used to diagnose the deficiencies of an existing source-term VG model, in this work the jBAY model.
KW - Continuous adjoint method
KW - Source-term model
KW - Vortex generators
KW - Finite-volume method
KW - Computational Fluid Dynamics (CFD)
UR - http://resolver.tudelft.nl/uuid:1ade02d3-c3a8-4a8a-a850-4cfea9e95c19
U2 - 10.1016/j.compfluid.2017.12.009
DO - 10.1016/j.compfluid.2017.12.009
M3 - Article
SN - 0045-7930
VL - 162
SP - 139
EP - 151
JO - Computers & Fluids
JF - Computers & Fluids
ER -