Research Focus Areas:MIG thematic areas focus on problem-centric solution approach rather than solution-centric problem-search. Working in collaboration, MIG customize methodologies and carry out innovative applied research in the area of aerodynamics, flight mechanics & control. Currently, MIG researchers are actively pursuing following thematic / focus areas:
1.Aerodynamics, Flight Mechanics & Control of Fixed-Wing Small Unmanned Aircraft Systems.
Small Unmanned Aircraft Systems with the wing span less than one meter have gained significant attention in recent years because of its versatility in multi-faceted mission profiles. Conceptually, these systems should be capable of immediate deployment and operated through a palm sized ground control station by a single operator. Even though this area of research is pretty renowned in academia for the last two decades, however, lot of challenges impedes its large-scale operational deployment.
Typical attributes associated with the aerodynamics of Small Unmanned Aircraft Systems (UAS) are low Reynolds number, low altitude flying environments and low aspect ratio platforms. These attributes give birth to several challenges such as poor aerodynamic performance, nonlinear/complex lift patterns and reduced gust tolerance. Specifically we are working on:
- Configuration Aerodynamics: We are exploring biplanes, flexible membrane wings and different morphing configurations to enhance aerodynamic performance in this flight regime.
- Utilization of Polhamus method to segregate potential & vortex lift associated with these platforms and generate an alternate way of assessing aerodynamic contributions.
- Engineering the nature-inspired corrugation for small UAS platforms.
Similarly, the attributes associated with the flight mechanics and control for these systems are expanded flight envelopes, low moment of inertia and small stability margins with high design versatility. These attributes give birth to the several challenges out of which a few are: triggering of nonlinear phenomena, dynamic stability estimation and flight performance prediction. We are currently working on following approaches to build new knowledge in this area:
- Evaluation of dynamic stability derivatives using CFD. Our major focus is tilted towards studying the effect of geometric variables on dynamic damping behavior.
- Different optimization algorithms are used to study versatile trajectories associated with small UAS such as: transitions between hover & cruise, perching & dynamic soaring maneuvers. One of our recent initiatives is the characterization of perching maneuvers performed by flying insects.
- Development of surrogate models to evaluate the performance & find underlying scalability trends between geometric & performance parameters.
2. Limit Cycle Oscillations in Aerospace Systems:
Limit Cycles are self-sustained oscillations manifested by dynamic systems that are mostly undesirable in aerospace applications. Linear systems theory is limited and cannot decipher the limit cycle characteristics in relation to the aircraft parameters. To overcome this limitation, nonlinear analysis is required.
Complex dynamic systems generally exhibit a mixture of fast and slow response. Some parameters of a certain system may govern the fast dynamic behavior while other may affect the slow dynamic response of the system. In order to fully understand the system so that desired alterations during design and development cycle can be made, understanding the response due to relevant parameters on the slow and fast system behavior can be vital. Generally, instabilities in slow behavior are less threatening than in the fast dynamics. The Multiple Time Scales (MTS) approach separates these slow and fast manifolds of the system explicitly and is based exactly on this separation idea. The idea of the extension is to transform the existing dimension of time to a multiple dimensional space. Since many physical systems of interest exhibit multiple natural time scales, the MTS method is applicable to a wide range of problems. One example is the separation of phugoid mode (slow varying manifold) and short-period mode (fast varying manifold) in aircraft longitudinal dynamics.
Currently, we are working on following problems:
- Effect of low-aspect ratio rectangular wings on wing-rock.
- Effect of compressor characteristic curve on surge in axial flow compressors.
- LCO of Atmospheric Entry Vehicles in low supersonic regime.
- Pressure Oscillations inside Combustion Chamber of solid rocket motors.
3.Aerodynamics & Flight Mechanics of Supersonic Blunt Bodies with Active / Passive Flow Control.
The main scientific aim of this project is to reduce and modify the nose shock wave in order to generate smaller drag force and / or better conditions to overcome sonic barrier and to diminish sonic boom intensity.
The main motivation of this project is to understand the complex shock wave pattern formed by the nose of the aircraft and alleviate its adverse contributions that are high drag, high acoustic signature and high aerodynamic heating.Specifically, feasibility of different passive, active and hybrid flow control techniques to tailor the shock wave characteristics are currently investigated. In near future, effect of active flow control techniques on static and dynamic stability characteristics will also be investigated.
The research in this area is pursued through active collaboration with Dr. Laurent Dala, Northumbria University, UK.
4.Design & Development of Energy-Efficient Electric Fan Blades
This research pertains to the improvement in the energy efficiency of pedestal and ceiling fans through aerodynamic design refinement of blades. The fan industry of Pakistan is renowned at national and international levels. This is widely considered as an elite sector that is fulfilling national needs of domestic electric fans as well as exporting their products. Gujrat, a hub of fan industry hosts about 300 Small and Medium Enterprises (SMEs). These SMEs are facing tough competition because of advancement in technology, requirement of energy efficiency and failure to comply national / global quality standards. As a result, different fan manufacturers are approaching scientific experts in academia to improve their product design. In this research, we will be collaborating with STARCOŽ Fans, Gujrat, an industry that has evolved during the last 10 years from a small setup to a substantially large enterprise with primary focus on ceiling, pedestal and wall-mounted fan manufacturing. MIG has already executed a small-scale project with STARCOŽ Fans in the past in which one ceiling fan blade design of one product was optimized. National University of Sciences & Technology (NUST) and STARCOŽ Fans intend to expand the scope of collaboration. In this research, aerodynamics body of knowledge is used to refine / redesign / optimize the pedestal and ceiling fan blade designs through computational and experimental approaches. The results produced through this research are lucrative in the sense that implementation cost of the solutions can boost the quality of products with zero investment cost. Moreover, the proposed solutions do not require any improvisation in existing production line.