Task 1: Literature survey, design and manufacture of models for SBLI have been conducted. Test models consists of a flat plate on which one of the two compression ramps were mounted at a distance of 40 mm from the leading edge.
Task 2: Ludwieg tube tunnel experiments were conducted with the test models, with time resolved schlieren imaging and surface pressure measurements.
Task 3: Detailed time series analysis of the measurements were performed.
Task 4: Flow field induced by a novel DBD actuator configuration in quiescent air, and the flow control using the DBD actuator in cavity flow (having some analogous features with SBLI) simulated in University of National Wind Tunnel Facility are studied.
- Overview of research results:
1) Analysis and characterization of SBLI with leading edge separation: Overall, statistically steady flow was observed with the 45 degree angle compression corner; the low amplitude pressure fluctuation had Strouhal number of ~0.09 which was an order of magnitude higher than those reported in the literature for turbulent SBLI, and comparisons were done with cavity shear layer mode. With 90 degree angle compression corner (step), large amplitude to and fro motion of shock structure, similar to pulsation over spiked circular cylinders (the analogous axisymmetric case) was observed; though the flow with step is non-periodic unlike the pulsation over spiked circular cylinder. Overall, the analysis and characterization suggested bifurcations in unsteady SBLI as the parameters are varied
2) Flow control by DBD actuator: Time resolved planar particle image velocimetry investigations of the DBD flow control of low speed cavity flow demonstrated suppression of cavity oscillations. The present DBD generated flow speeds are not sufficient to control hypersonic flows. However, the control mechanism of the novel configuration at low speeds gives some valuable suggestions which can be extended to high speeds.
- Publications/presentations in high quality international open access journals, conferences and workshops are being pursued enthusiastically (3 journal papers have been written; 1 conferences were attended; 2 more journal articles are in preparation)
- Collaboration activities: Prof Jagadeesh (Indian Institute of Science, Bangalore, India) joined our research activities related to Ludwieg tube tunnel experiments.
- Industrial collaboration and engagement: We had meetings with Dr Michael West (BAE Systems) and Dr. David Evans (Fluid Gravity Engineering Ltd.) for a collaborative project on Future UK Small Payload Launcher (FSPL, June-December 2016; August-October 2017), and discussed with them regularly on the outcomes of the present project which are relevant to FSPL; Dr Sriram Rengarajan and Prof Konstantinos Kontis contributed to the construction of new facility since May 2017 for a space mission proposed by ESTEC/ESA. Dr Sriram Rengarajan and Prof Konstantinos Kontis initiated a project on automotive flow control using DBD in collaboration with Jaguar Land Rover (August 2017), which was inspired from the outcomes of the present project.
- Training: Dr Sriram Rengarajan has been actively engaging in the supervision of UoG and Ph.D. students; He has been in charge of the set-up of number of facilities and associated diagnostics and heavily involved in the running of the research group; He also engaged in teaching activities in the Aerospace program at UoG, as a tutor in two courses from January-April 2016; UoG provided him with early career development program (2016-2017): Ph.D. supervision and research collaboration engagement as well as laser safety training.
