Non-intrusive flight trajectory manipulation of high-speed munitions using non-linear shock/boundary layer interactions
Abstract
The vision of the proposed research is to explore a new paradigm for anti-air interception wherein the trajectory of adversary supersonic/hypersonic projectiles will be remotely altered using reusable interceptors. The main focus is on laser-based interceptors -- the objective is to investigate and evaluate means to usefully manipulate the non-linear shock boundary layer interactions present around control fins using laser-induced perturbation of incoming boundary layer. The central questions to be addressed include: 1) Can one generate trajectory manipulation over a wide range of Mach numbers and fin-shock strengths? 2) If yes, what is the maximum perturbation force one can obtain for a given perturbation magnitude? 3) What is the domain of the sensitive perturbation regions that generate sizeable control force and moment alteration? In other words, how forgiving is the proposed trajectory manipulation approach to inaccuracies in the interception locations?Complementary experiments and computations will be performed on a sharp fin mounted on a hollow semicircular cylinder surface that represents one half of a missile geometry. To keep the flow configuration simple, only one fin will be employed to avoid the flow complexity that arises from shock crossings of multi-fin configurations of practical munitions. Two fin angles, one corresponding to attached and other corresponding to separated boundary layer, will be employed to evaluate the central questions at different trajectory phases of the missiles. Two boundary layer perturbation strategies will be tested that are representative of laser interception. These include the deformation of the missile surface due to laser induced material scouring/shocking, and local missile surface heating due to laser beam incidence. Well characterized dimples will be made on the cylinder surface to simulate the laser-based material deformation, and a heated cylinder surface (with steady and unsteady heating) will be employed to evaluate the laser-based surface heating strategy.Changes in fin-normal forces and pitching/rolling/yawing moments caused by introducing perturbations of different strengths and locations will be determined by integrating the mean surface pressure field measured using pressure sensitive paint, and with CFD data. This provides a quantitative measure of the alterations in the control forces/moments caused by the perturbations as well as help map out the sensitive perturbation domain for appreciable changes. Detailed investigations of the flow interactions between the perturbed boundary layer and the flow field around the control fin will be performed to help with the development of high-fidelity trajectory prediction capabilities as well as for the optimization of perturbation strategies. For these studies, off-surface flow-field measurements will be made using stereoscopic particle image velocimetry technique that provides three-component velocity fields in the measurement planes. These measurements will be made at 10 Hz and 10 kHz repetition rates to capture the mean and unsteady flow interactions that engender the force/moment changes. The computations will build on the experiments and evaluate the control force/moment changes in more realistic laser interception situation that occur with simultaneous surface heating and material deformation. The computations will further extend the evaluation Mach numbers from supersonic through hypersonic speed regimes.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 06, 2021
- Source ID
- N000142112238
Entities
People
- Venkateswaran Narayanaswamy
Organizations
- North Carolina State University
- Office of Naval Research
- United States Navy