Catálogo de publicaciones - libros

Control of transition in plane channel flows can be achieved by applying linear optimal control to the state equations obtained by a suitable discretization of the Fourier transformed and linearized Navier-Stokes equations. Different flow properties can be affected through the choice of the objective function used for optimal control. In the present work, various control algorithms have been obtained by using full state feedback. The objective function has been chosen using a measure of the energy of flow perturbations, with various weight matrices. performance of the controllers thus designed has been studied.

Control of transition in plane channel flows can be achieved by applying linear control to a suitable reduced-order system of state equations, with an appropriate state estimator. In the present work, a comparative study of various estimatorbased controllers has been carried out. The state estimators have been designed as Kalman filters using various covariance matrices. The performance of linear optimal controllers based on these estimators has been studied by numerical integrations.

The effect of uniform wall suction and blowing on a turbulent boundary layer was experimentally investigated. It was discovered that the development of the boundary layer is suppressed by suction and promoted by blowing. The turbulence intensity in the outer part increases with blowing and decreases with suction, however in the inner part the intensity is only slightly affected if scaled with the free-stream velocity.

Stability of compliant pipe flow has been studied, by considering a viscoelastic pipe, with an outer rigid shroud, and, with Hagen - Poiseuille .ow through the pipe. The work includes normal compliance studies, and combined normal plus tangential compliance studies. Both axisymmetric and non-axisymmetric disturbances have been considered.

The main aim of the present work is to develop a robust and efficient oneequation model based on the subgrid scale (SGS) kinetic energy for the large eddy simulation (LES) and test on a fully developed channel flow with constant spanwise rotation. The proposed model combines the advantages of existing one-equation SGS models. The proposed model first tested on fully developed channel flow and compared with some existing models results. Second, efficiency of this model has been demonstrated by the prediction of relaminarization of grid scale (GS) turbulence on the suction side of the spanwise rotating channel flow.