Search for dissertations about: "optimal initial disturbances"

Showing result 1 - 5 of 10 swedish dissertations containing the words optimal initial disturbances.

2. 1. Optimisation and control of boundary layer flows

   Author : Antonios Monokrousos; Dan S. Henningson; Per Lötstedt; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer; control; estimation; optimal disturbances; Lagrange method; Engineering mechanics; Teknisk mekanik;

   Abstract : Both optimal disturbances and optimal control are studied by means of numerical simulations for the case of the flat-plate boundary-layer flow. The optimisation method is the Lagrange multiplier technique where the objective function is the kinetic energy of the flow perturbations and the constraints involve the linearised Navier–Stokes equations. READ MORE

4. 2. Optimisation and control of shear flows

   Author : Antonios Monokrousos; Dan S. Henningson; Laurette Tuckerman; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; shear flows; flow control; optimal disturbances; Lagrange method; transition to turbulence; non-linear dynamics; Engineering mechanics; Teknisk mekanik;

   Abstract : Transition to turbulence and flow control are studied by means of numerical simulations for different simple shear flows. Linear and non-linear optimisation methods using the Lagrange multiplier technique are employed. READ MORE

5. 3. On optimization of natural convection flows

   Author : Clio Saglietti; Dan S. Henningson; Kurt Maute; KTH; []
   Keywords : Natural convection cooling; topology optimization; flow optimization; heat sink; conjugate heat transfer; differentially heated cavity; optimal initial disturbances; adjoint optimization;

   Abstract : Two different techniques are presented for enhancing the thermal  performance of natural convection cooled heat sinks. The physics is  described by solving the conjugate heat transfer problem with a  spectral element method. The temperature distribution is computed in  two sub-domains, whose solution is then conjugated. READ MORE

6. 4. Stability and Receptivity of Three-Dimensional Boundary Layers

   Author : David Tempelmann; Dan Henningson; Stefan Hein; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; stability; optimal growth; three-dimensional boundary layers; parabolised stability equations; adjoint PSE; crossflow instability; Fluid mechanics; Strömningsmekanik;

   Abstract : The stability and the receptivity of three-dimensional flat plate boundary layers is studied employing parabolised stability equations. These allow for computationally efficient parametric studies. Two different sets of equations are used. READ MORE

7. 5. Receptivity of crossflow-dominated boundary layers

   Author : David Tempelmann; Ardeshir Hanifi; Dan Henningson; Anatoli Tumin; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; three-dimensional boundary layers; optimal growth; adjoint solutions; swept wing;

   Abstract : This thesis deals with receptivity mechanisms of three-dimensional, crossflow-dominated boundary layers. The receptivity of two model problems, a swept-flat-plate and a swept-wing boundary layer, is investigated by solving the parabolised stability equations (PSE) as well as by performing direct numerical simulations (DNS). READ MORE