Ambareen Khan¹, Sher Afghan Khan², Mohammed Nishat Akhtar^1,*, Abdul Aabid^3,*, Muneer Baig³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 2007-2028, 2024, DOI:10.32604/fdmp.2024.049368 - 23 August 2024

Abstract When better fuel-air mixing in the combustion chamber or a reduction in base drag are required in vehicles, rockets, and aeroplanes, the base pressure control is activated. Controlling the base pressure and drag is necessary in both scenarios. In this work, semi-circular ribs with varying diameters (2, 4, and 6 mm) positioned at six distinct positions (0.5D, 1D, 1.5D, 2D, 3D, and 4D) inside a square duct with a side of 15 mm are proposed as an efficient way to apply the passive control technique. In-depth research is done on optimising rib size for various More > Graphic Abstract

Vigneshvaran Sethuraman¹, Parvathy Rajendran^1,*, Sher Afghan Khan², Abdul Aabid³, Muneer Baig³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.8, pp. 1847-1866, 2024, DOI:10.32604/fdmp.2024.049441 - 06 August 2024

Abstract This study deals with base pressure management in a duct for various values of the Mach number (M), namely, Mach number corresponding to sonic and four supersonic conditions. In addition to the Mach number, the nozzle pressure ratio (NPR), the area ratio, the rib dimension, and the duct length are influential parameters. The following specific values are examined at M = 1, 1.36, 1.64, and 2, and NPRs between 1.5 and 10. The base pressure is determined by positioning ribs of varying heights at predetermined intervals throughout the length of the square duct. When the… More >

Jaimon Dennis Quadros¹, Sher Afghan Khan², Abdul Aabid^3,*, Muneer Baig³

CMES-Computer Modeling in Engineering & Sciences, Vol.137, No.3, pp. 2331-2352, 2023, DOI:10.32604/cmes.2023.028925 - 03 August 2023

Abstract The application of abruptly enlarged flows to adjust the drag of aerodynamic vehicles using machine learning models has not been investigated previously. The process variables (Mach number (M), nozzle pressure ratio (η), area ratio (α), and length to diameter ratio (γ )) were numerically explored to address several aspects of this process, namely base pressure (β) and base pressure with cavity (β_cav). In this work, the optimal base pressure is determined using the PCA-BAS-ENN based algorithm to modify the base pressure presetting accuracy, thereby regulating the base drag required for smooth flow of aerodynamic vehicles. Based… More > Graphic Abstract

Ridwan¹, Sher Afghan Khan^1,*, Jaffar Syed Mohamed Ali¹, Mohd. Azan Mohammed Sapardi¹, Abdul Aabid²

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.6, pp. 1655-1678, 2023, DOI:10.32604/fdmp.2023.025230 - 30 January 2023

Abstract In the present study, the base pressure variations induced by the presence of a cavity, known to have a strong influence of the behaviour of supersonic projectiles, are investigated through numerical solution of the balance equations for mass, momentum, and energy. An area ratio of four is considered and numerical simulations are carried out at Mach M = 1.2, 1.4, 1.6, and 1.8 assuming no cavity or cavity locations 0.5D, 1D, 1.5D, and 2D. The inlet pressure of the nozzle is considered as a flow variable. The Taguchi method is also used, and the considered More >

Nur Husnina Muhamad Zuraidi¹, Sher Afghan Khan^1,*, Abdul Aabid^2,*, Muneer Baig², Istiyaq Mudassir Shaiq³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.3, pp. 807-829, 2023, DOI:10.32604/fdmp.2023.023246 - 29 September 2022

Abstract In this study, a duct is considered and special attention is paid to a passive method for the control of the base pressure relying on the use of a cavity with a variable aspect ratio. The Mach number considered is 1.8, and the area ratio of the duct is 2.56. In particular, two cavities are examined, their sizes being 3:3 and 6:3. The used L/D spans the interval 1–10 while the NPRs (nozzle pressure ratio) range from 2 to 9. The results show that the control becomes effective once the nozzles are correctly expanded or More >

Abdul Aabid^1,*, Sher Afghan Khan², Muneer Baig¹

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.6, pp. 1877-1900, 2022, DOI:10.32604/fdmp.2022.021860 - 27 June 2022

Abstract A method based on microjets is implemented to control the flow properties in a convergent-divergent nozzle undergoing a sudden expansion. Three different variants of this active control technique are explored numerically by means of a finite-volume method for compressible fluid flow: with the first one, the control is implemented at the base, with the second at the wall, while the third one may be regarded as a combination of these. When jets are over-expanded, the control is not very effective. However, when a favourable pressure gradient is established in the nozzle, the control becomes effective, More >