Search for dissertations about: "Unsteady flow on boundary layer"

Showing result 1 - 5 of 27 swedish dissertations containing the words Unsteady flow on boundary layer.

2. 1. Effects of free-stream turbulence and three-dimensional roughness on boundary layer transition

   Author : Santhosh Babu Mamidala; Jens H. M. Fransson; Bengt E. G. Fallenius; Jonathan Morrison; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary-layer transition; intermittency; free-stream turbulence; electret microphones; isolated roughness; sinuous instability; varicose instability; Engineering Mechanics; Teknisk mekanik;

   Abstract : External disturbances such as free-stream turbulence (FST), and isolated three-dimensional roughness are strong disturbance sources to the laminar boundary layers (BLs), which can lead to a rapid transition to turbulence. The transition process eventuates to increase in skin-friction coefficient and heat transfer rate and hence, both of the aforementioned disturbance sources have practical importance. READ MORE

4. 2. Numerical and Experimental study of shock boundary layer interaction in unsteady transonic flow

   Author : Olivier Bron; KTH; []
   Keywords : Shock Boundary Layer Interaction; Shock Motion; Unsteady Flows; Nozzle Flows; Potential Interaction; Back Pressure Perturbations;

   Abstract : A prerequisite for aeroelastic stability prediction inturbomachines is the understanding of the fluctuatingaerodynamic forces acting on the blades. Unsteady transonicflows are complex because of mutual interactions betweentravelling pressure waves, outlet disturbances, shock motion,and fluctuating turbulent boundary layers. READ MORE

5. 3. Unsteady Numerical Simulations of Flow around Heavy Vehicles, Trains and Passenger Cars

   Author : Jan Östh; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Large Eddy Simulation; fluid dynamics; bluff body flows; flow structures; vehicle aerodynamics; flow control; flow physics; truck aerodynamics; train aerodynamics; car aerodynamics;

   Abstract : In this thesis several simulations have been carried out aimed at improving the knowledgeof vehicle aerodynamics and improving the flow around vehicles with respect to theaerodynamic drag. Four flows around different simplified vehicles have been considered. READ MORE

6. 4. Supersonic flow separation with application to rocket engine nozzles

   Author : Jan Östlund; KTH; []
   Keywords : turbulent; boundary layer; shock wave; interaction; overexpanded; rocket nozzle; flow separation; control; side-load; experiments; models; review;

   Abstract : The increasing demand for higher performance in rocketlaunchers promotes the development of nozzles with higherperformance, which basically is achieved by increasing theexpansion ratio. However, this may lead to flow separation andensuing instationary, asymmetric forces, so-called side-loads,which may present life-limiting constraints on both the nozzleitself and other engine components. READ MORE

7. 5. Numerical studies of bypass transition in the Blasius boundary layer

   Author : Luca Brandt; KTH; []
   Keywords : Fluid Mechanics; laminar-turbulent transition; boundary layer flow; transient growth; streamwise streaks; secondary instability;

   Abstract : Experimental findings show that transition from laminar toturbulent ow may occur also if the exponentially growingperturbations, eigensolutions to the linearised disturbanceequations, are damped. An alternative non-modal growthmechanism has been recently identi fied, also based on thelinear approximation. READ MORE