Dynamic Stall Workshop
Abstract
Dynamic stall is an unsteady aerodynamic phenomenon resulting from the rapid angle of attack change of a lifting surface during which the flow separates and then later reattaches. Dynamic stall is characterized by complex flow field phenomena including shear layers and vortices that interact with one another and the airfoil. Dynamic stall on a rotor can be triggered by large angle of attack excursions, blade-vortex interaction, and shocks. This workshop is designed to impart to the broader community the advances and current state of the art in the understanding and prediction of rotorcraft-related dynamic stall. Quantitative predictors of dynamic stall are not readily available for new rotor design needed for the U.S. ArmyÕs Joint Multi-Role (JMR) helicopter program or Future Vertical Lift (FVL) initiative. The ability to predict dynamic stall and eliminate it from the flight envelope is necessary to improve upon current safety standards. Dynamic stall behavior in rotorcraft applications is dependent on a large variation of conditions, and its complex and nonlinear behavior has been the focus of much research, including experimental and computational efforts. It is prohibitively expensive to run experiments, and current lower fidelity numerical analysis is not sufficient to capture the details of dynamic stall so computational fluid dynamics (CFD) or computational fluid dynamics-computational structural dynamics (CFD-CSD) analyses have also been investigated. Extensive experimentation in the prior century has led to the development of this qualitative sequence of events that define the dynamic stall event. These were primarily on two-dimensional, non-rotating systems. More recent research has shown that the earlier two-dimensional efforts were the most difficult and least comparable to dynamic stall events that occur on current rotors. New lower fidelity methods for comprehensive codes developed since 2008 have improved the ability to predict dynamic stall, and recent correlations with advanced numerical CFD methods have demonstrated their ability to capture the physical phenomena that drive many dynamic stall events. This workshop is planned to disseminate these new findings and methodologies to the research and engineering communities who are intimately involved in dynamic stall. It is important that these capabilities are more widely known; even with the plethora of peer-reviewed journals, there is still significant duplication on topics that have already been resolved. It is further necessary to determine the future path of research in this area; what gaps in knowledge or roadblocks in methods development still remain? In particular, active flow control (AFC) of dynamic stall has had significant funding in the past, but there are still no systems installed on current vehicles. Are there physics that can be exploited to make AFC viable? Are there results from dynamic stall research on rotorcraft be leveraged in other fields such as fixed wing, wind/wave energy, and engine systems? Panel sessions to discuss and disseminate these questions and others will be held.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 22, 2019
- Source ID
- W911NF1810291
Entities
People
- Marilyn Smith
Organizations
- Army Contracting Command
- Georgia Tech Research Corporation
- United States Army