https://doi.org/10.1140/epjs/s11734-025-02009-9
Regular Article
Numerical analysis of infrared emissions from jet plumes issuing from different nozzle geometries
1
Department of Aerospace Engineering and Applied Mechanics, Indian Institute of Engineering Science and Technology Shibpur, 711103, Howrah, West Bengal, India
2
Department of Aerospace Engineering, Indian Institute of Technology Kanpur, 208016, Kanpur, Uttar Pradesh, India
3
Department of Mechanical Engineering, Shri Guru Gobind Singhji Institute of Engineering and Technology, Nanded, Maharashtra, India
4
GE Aerospace, Bengaluru, India
a
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Received:
7
July
2025
Accepted:
30
September
2025
Published online:
14
October
2025
This work presents a comprehensive numerical investigation into the infrared (IR) signature characteristics of aircraft exhaust plumes for various non-axisymmetric nozzle configurations. Three-dimensional Reynolds-Averaged Navier–Stokes (RANS) simulations, using the k-
SST turbulence model, are conducted for three nozzle geometries viz. circular, elliptical, and serpentine elliptical under sea-level and 9 km altitude conditions. Flow field variables including temperature, pressure, and species mass fractions are extracted and coupled with spectroscopic data from the HITRAN2012 database to compute wavelength-resolved spectral intensities using the radiative transfer equation. The results demonstrate that non-axisymmetric nozzles substantially reduce the IR signature by enhancing plume mixing and shortening the thermal core length. The non-serpentine elliptical nozzle achieves up to 6.7% reduction in exit temperature and a 57% reduction in core length relative to the circular configuration. Peak IR emissions are suppressed in the critical wavelength bands of 2.7 
m, 4.3 m, and 5.5–7 m, with up to 50% intensity reduction observed in the rear aspect. Altitude-dependent atmospheric transmittance effects are also quantified, showing lower radiation absorption and modified intensity distributions at higher altitudes due to reduced H2O concentration. The computational framework combines high-resolution plume flow modeling with spectral radiative analysis to capture altitude, geometry, and observer-position effects with precision. These findings underscore the viability of geometrically optimized nozzles as a passive and aerodynamically efficient solution for infrared stealth, supporting design strategies for advanced airborne platforms operating in thermally contested environments.
Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjs/s11734-025-02009-9.
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Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
