Experimental Investigation of the Application of Microramp Flow Control to an Oblique Shock Interaction


Book Description

The effectiveness of microramp flow control devices in controlling an oblique shock interaction was tested in the 15- by 15-Centimeter Supersonic Wind Tunnel at NASA Glenn Research Center. Fifteen microramp geometries were tested varying the height, chord length, and spacing between ramps. Measurements of the boundary layer properties downstream of the shock reflection were analyzed using design of experiments methods. Results from main effects, D-optimal, full factorial, and central composite designs were compared. The designs provided consistent results for a single variable optimization. Hirt, Stefanie M. and Anderson, Bernhard H. Glenn Research Center OBLIQUE SHOCK WAVES; BOUNDARY LAYERS; SHOCK WAVE INTERACTION; EXPERIMENT DESIGN; FACTORIAL DESIGN; SUPERSONIC WIND TUNNELS; SPACING




Understanding Micro-Ramp Control of Supersonic Shock Wave Boundary Layer Interactions


Book Description

This research investigated the potential of micro-ramp sub-boundary layer vortex generators for flow control of oblique shock boundary layer interactions (SBLIs) which is relevant to supersonic engine inlets. These novel devices can delay shock-induced separation and improve boundary layer health, thus offering the potential to reduce the bleed requirement in intakes. Micro-ramp Experiments have been conducted at Mach 2.5, to determine the nature of flow controlled by micro-ramps and investigate their ability to delay separation in a reflected shock interaction. Various ramp sizes between 30% and 90% of boundary layer thickness were investigated. The details of the vortical flow generated by such devices was identified. The general flow features were found to scale with device height and it is suggested that smaller devices need to be placed closer to the expected adverse pressure gradients. When applied to a separated oblique shock SBLI micro-ramps were not observed to eliminate flow separation, although they were shown to break up separated regions. Other performance indicators across the SBLI were also improved through the application of the devices.










High Order Large Eddy Simulation for Shock-Boundary Layer Interaction Control by a Micro-ramp Vortex Generator


Book Description

This volume presents an implicitly implemented large eddy simulation (ILES) by using the fifth order bandwidth-optimized WENO scheme. The chosen method is applied to make comprehensive studies on ramp flows with and without control at Mach 2.5 and Re=5760. Flow control in the form of microramp vortex generators (MVG) is applied. The results show that a MVG can distinctly reduce the separation zone at the ramp corner and lower the boundary layer shape factor under simulated conditions. A series of new findings about the MVG-ramp flow are obtained, including structures relevant to surface pressure, three-dimensional structures of the re-compression shock waves, a complete surface separation pattern, momentum deficit and a new secondary vortex system. A new mechanism of shock-boundary layer interaction control by MVG associated with a series of vortex rings is also presented. Vortex rings strongly interact with air flow and play an important role in the separation zone reduction. Additionally, readers will learn about the governing equation, boundary condition, high quality grid generation, high order shock capturing scheme and DNS inflow condition in detail. This volume will, therefore, serve as a useful reference for aerospace researchers using LES methods to study shock boundary layer interaction and supersonic flow control.




Shock Wave-Boundary-Layer Interactions


Book Description

Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.




High Order LES for Supersonic Ramp Flow Control with MVG


Book Description

An implicitly implemented large eddy simulation by using the fifth order bandwidth-optimized WENO scheme is applied to make comprehensive studies on ramp flows with and without control at Mach 2.5 and Re =5760. Flow control in the form of microramp vortex generators (MVG) is applied. The results show that MVG can distinctly reduce the separation zone at the ramp corner and lower the boundary layer shape factor under the condition of the computation. A series of new findings are obtained about the MVG-ramp flow including the threedimensional vortex structure generated by MVG. The mechanism about the formation vortex ring structure and its interaction with shock wave at the ramp corner is deeply studied. Vortex rings strongly interact with the flow and play an important role in the separation zone reduction. It shows that the ring structure does not break down and keeps it topology after penetrating the strong shock wave and the oblique shocks is influenced a lot by the induced flow field from rings. The bump of the 3D shock wave surface is discovered and its mechanism is explained.




Parallel Computational Fluid Dynamics


Book Description

This book constitutes the refereed proceedings of the 25th International Conference on Parallel Computational Fluid Dynamics, ParCFD 2013, held in Changsha, China, in May 2013. The 35 revised full papers presented were carefully reviewed and selected from more than 240 submissions. The papers address issues such as parallel algorithms, developments in software tools and environments, unstructured adaptive mesh applications, industrial applications, atmospheric and oceanic global simulation, interdisciplinary applications and evaluation of computer architectures and software environments.