This master thesis deals with the optimal initial perturbation problem for a 1D unsteady self-similar ablation flow in an inertial confinement fusion context. The physical modelling consists of the compressible Euler equations with nonlinear heat conduction. The base flow and linear 3D perturbations are computed using a multidomain Chebyshev collocation method. Longitudinal optimal initial perturbations are computed by means of a non-modal analysis method for stationary perturbation evolution operators (Schmid, 2001 & 2007) after transformation of the time-dependent perturbation problem. Results of optimal gain and initial perturbation differ significantly from those produced by a non-stationary direct-adjoint method (Varillon, 2019). This discrepancy is analyzed to be a consequence of a diagonalization failure of the discrete perturbation evolution operator.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-346943 |
| Date | January 2024 |
| Creators | Gallin, Adrien |
| Publisher | KTH, Skolan för teknikvetenskap (SCI) |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | TRITA-SCI-GRU ; 2024:058 |
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