Session: 10.4.3 - Vortex Dynamics III

Paper Number: 158711

158711 - Investigating the Integro-Differential Scheme Computational Capability to Predict Vortex Dominated Flow Fields 

Abstract: 

It is well established that separation-induced vortex flows are important considerations to the design of advanced military flight concepts. In fact, existing military vehicles are designed to operate well outside of the steady, attached flow regimes, where the flow field is well behaved and the flight vehicle performance is predictable. The flow fields in which future military flight vehicles are expected to maneuver are dominated by vortices and eddies, and considered to be fully turbulent. In addition, vortex dominated flows are often highly unsteady, and not readily amendable to accurate numerical simulations nor predictions. The investigations carried out by several CFD researchers indicated that the shortcomings in accurately capturing the unsteady fluid physics within vortex dominated flows can be traced to (i) the existing deficiencies of existing turbulent models and (ii) the ‘dispersive and dissipative’ characteristics of existing numerical methods. Specifically, the numerical investigations of vortex dominated flows, such as helicopter related flow fields, which involve complex flow phenomena are often not adequately resolved by advanced RANS models. Therefore, improved numerical methods, especially those with vortex and eddy capturing and tracking capabilities are required.

Over the past decade, significant enhancements in computational fluid dynamics (CFD) techniques have led to the development and use of improved numerical methods, some of which have demonstrated the potential to predict the formation of eddies and the generation of highly complex vortex dominated flow fields. Recently, an improved numerical concept, called the Integro-Differential Scheme, was formulated for use with the unsteady Navier-Stokes equations to simulate highly complex and unsteady flow fields. In this work, the objective is to demonstrate the capabilities of an improved numerical concept with the potential to resolve the physics within highly vortex flow fields. To this end, a series of existing vortex dominated flow field problems will be numerically formulated and solved. Among the list of CFD problems to be solved are (i) the vortex boundary-layer interaction, (ii) the vortex-reflected shock boundary layer problem, (iii) the vortex-normal shock interaction problem, (iv) the contact surface problem that leads to the creation of eddies and vortices, (vi) the jet flow problem that leads to the creation of eddies and vortices, and the (iv) the bluff body problem leading to wake generation and shedding. These CFD problems will be analyzed over a wide range of Reynolds and Mach numbers, and their results compared to those of available experimental data and the existing solutions derived from LES and DNS methods. After a detailed analysis, the physics capturing capability of the numerical method will be analyzed, its error handling characteristics will be determined and its veracity as a CFD tool for analyzing ‘vortex dominated flows’ will be established.

Presenting Author: Frederick Ferguson North Carolina A&T State University

Presenting Author Biography: Dr. Frederick Ferguson
Professor and Chair, ME Department, NCAT

Dr. Frederick Ferguson is a Professor in the Mechanical Engineering Department at North Carolina A&T State University (NCAT). He currently serves as the chair for the Department. In the past, he served as the Program Manager for Fluid Dynamics Program at the Army Research Office (ARO) (from Dec., 2009 through Dec., 2013). At NCAT, he served as the director for the Center for Aerospace Research from 1997 until 2009. Dr. Ferguson received his PhD. in Aerospace Engineering from the University of Maryland in 1993 and a MS. in Applied Mathematics from Kharkov State University in the former Soviet Union in 1986. He speaks the Russian language fluently. Dr. Ferguson is considered an expert in the areas of Computational Fluid Dynamics, Hypersonic Waveriders and Scramjet Propulsion Systems.
Currently, Dr. Ferguson and his students have created a CFD numerical code that is capable of generating solutions to the full set of Navier-Stokes Equations for a wide class of boundary conditions. The CFD code is capable of generating solutions under realistic aircraft operating conditions, while delivering results that contains all the required flow physics. Additionally, Dr. Ferguson is an expert in the design of hypersonic vehicle configurations using inverse numerical techniques, and has contributed to the expansion of the waverider design concept to include the design of a tip-to-tail vehicle. He currently conducts research in high speed aerodynamics, and is working on the development of efficient algorithms for simulating complex viscous flows in three dimensions; including turbulent flow fields in which finite-rate chemistry effects are dominant. In the past, Dr. Ferguson has managed research projects in the following areas: UAVs, Reusable launch vehicle (RLV), International Space Station (ISS), optimized aerospace vehicle design, software safety and image analysis and processing. At NCAT, Dr. Ferguson research projects have served to satisfied the graduation requirements of over 35 MS and PhD students, and has authored and/or co-authored over 120 scientific articles. Dr. Ferguson also worked as an experimentalist for over ten years. At AEDAR Corporation, he was actively involved with scientists from JPL in the implementation and mapping of artificial intelligent algorithms (Fuzzy logic, expert systems, and Neural Networks) to field processing gate arrays (FPGAs) in the construction of affordable reconfigurable hardware. Some of his past research activities include multi-target tracking and the design of thermal systems for reentry vehicle. Earlier in his career, he worked at PALL Corporation in Long Island, NY, where he was involved in the design and manufacturing of aerosol filters for the semi-conductor industry.