# zbMATH — the first resource for mathematics

3D global optimal forcing and response of the supersonic boundary layer. (English) Zbl 1453.76194
Summary: 3D optimal forcing and response of a 2D supersonic boundary layer are obtained by computing the largest singular value and the associated singular vectors of the global resolvent matrix. This approach allows to take into account both convective-type and component-type non-normalities responsible for the non-modal growth of perturbations in noise selective amplifier flows. It is moreover a fully non-parallel approach that does not require any particular assumptions on the baseflow. The numerical method is based on the explicit calculation of the Jacobian matrix proposed by [C. Mettot et al., J. Comput. Phys. 269, 234–258 (2014; Zbl 1349.76129)] for 2D perturbations. This strategy uses the numerical residual of the compressible Navier-Stokes equations imported from a finite-volume solver that is then linearised employing a finite difference method. Extension to 3D perturbations, which are expanded into modes of wave number, is here proposed by decomposing the Jacobian matrix according to the direction of the derivatives contained in its coefficients. Validation is performed on a Blasius boundary layer and a supersonic boundary layer, in comparison respectively to global and local results. Application of the method to a boundary layer at $$M = 4.5$$ recovers three regions of receptivity in the frequency-transverse wave number space. Finally, the energy growth of each optimal response is studied and discussed.
Reviewer: Reviewer (Berlin)
##### MSC:
 76N20 Boundary-layer theory for compressible fluids and gas dynamics 76M12 Finite volume methods applied to problems in fluid mechanics 76J20 Supersonic flows 76N06 Compressible Navier-Stokes equations
##### Software:
AUSM; HE-E1GODF; MUMPS; PETSc
Full Text: