Diagnostic Investigation of Streamtube Flow Choking Effects on the Aerodynamic Performance of Transonic Aircraft

Rajendran, V and Sai Shankaran, B and Nandhan, AK and Krishnasamy, D and Sankar, V and Vignesh, S and Sanal Kumar, VR (2022) Diagnostic Investigation of Streamtube Flow Choking Effects on the Aerodynamic Performance of Transonic Aircraft. In: AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022, 3-7 Jan 2022, San Diego.

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Abstract

The phenomenological manifestation of the nanoscale Sanal flow choking V.R.S.Kumar et al., Nature Scientific Reports, 2021, DOI: 10.1038/s41598-021-94450-8 and streamtube flow choking V.R.S.Kumar et al., Physics of Fluids, 2021, DOI:10.1063/5.0040440 is a paradigm shift in the design optimization of transonic aircraft. In the first phase, the proof of the concept of boundary-layerblockage (BLB) persuaded flow-choking at aircraft-in-ground (AIG)-effect is reviewed and streamtube flow choking effects are discussed. When the ground clearance of an aircraft is relatively small, the developing BLB factor from both planes (the ground and the bottom surface of the aircraft) makes a transient fluid-throat, heading to the Sanal flow choking and supersonic flow development in the channel flow region. In this physical situation, the pressure ratio (Ptotal/Pstatic) at the region of flow choking is entirely a function of the heat capacity ratio of the fluid. In the second phase, streamtube flow choking effects on the aerodynamics performance of transonic aircraft is examined through in silico methodology. The 2D in silico simulations are carried out for stationary airfoils in ground effect and cruise conditions. Different types of airfoils are chosen for the diagnostic investigation to establish the phenomenon of streamtube flow choking during the transonic flying conditions of aircraft. We observed that the flow choking is more susceptible to the low wing aircraft flying in close proximity to the ground and/or sea with relatively high subsonic Mach number (M > 0.56) and the low angle of attack. At this flying condition, the underneath of the transonic aircraft (wing and/or fuselage) and the ground creates the convergent-divergent (CD) channel flow effect leading to Sanal flow choking at the critical total-to-static pressure ratio. We observed that streamtube compression and flow choking is more prone in regions where turbulent viscosity is relatively high. We conjectured that injecting microfluid jets with the high heat capacity ratio at the region ahead of streamtube flow choking can delay or negate the shock wave generation and can improve the aerodynamic performance of transonic aircraft. This diagnostic investigation is a pointer towards for increasing the drag divergence Mach number for the lucrative design optimization of highperformance transonic vehicles with improved propulsion and aerodynamic performances. © 2022, American Institute of Aeronautics and Astronautics Inc.. All rights reserved.

Item Type:	Conference Paper
Publication:	AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022
Publisher:	American Institute of Aeronautics and Astronautics Inc, AIAA
Additional Information:	The copyright for this article belongs to American Institute of Aeronautics and Astronautics Inc, AIAA
Keywords:	Angle of attack; Angle of attack indicators; Channel flow; Delta wing aircraft; Fuselages; Reynolds number; Specific heat; Transonic aerodynamics; Viscosity; Wings, Aero-dynamic performance; Choking effects; Condition; Design optimization; Flow choking; Ground clearance; In-silico; Nano scale; Paradigm shifts; Stream tubes, Supersonic aircraft
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	13 Feb 2022 08:44
Last Modified:	13 Feb 2022 08:44
URI:	http://eprints.iisc.ac.in/id/eprint/71358

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