Infrasonic attenuation in the upper mesosphere–lower thermosphere: A comparison between Navier–Stokes and Burnett predictions

Abstract

This paper presents the results of a pilot study comparing the use of continuum and non-continuum fluid dynamics to predict infrasound attenuation in the rarefied lower thermosphere. The continuum approach is embodied by the Navier-Stokes equations, while the non-continuum method is implemented via the Burnett equations [Proc. London Math. Soc. 39, 385-430 (1935); 40, 382-435 (1936)]. In the Burnett framework, the coupling between stress tensor and heat flux affects the dispersion equation, leading to an attenuation coefficient smaller than its Navier-Stokes counterpart by amounts of order 0.1 dB/km at 0.1 Hz, 10 dB/km at 1 Hz, and 100 dB/km at 10 Hz. It has been observed that many measured thermospheric arrivals are stronger than current predictions based on continuum mechanics. In this context, the consistently smaller Burnett-based absorption is cautiously encouraging.

Heat flux correlation for high-speed flow in the transitional regime

“…This poses challenges for numerical solution techniques, and analytical solutions are generally not possible with few exceptions Singh, Gavasane & Agrawal 2014). Despite these challenges, these hydrodynamics models have been successfully applied to low-speed rarefied problems, for which a number of important rarefied phenomena have been captured (Zohar et al 2002;He, Tang & Pu 2008;Gu, Emerson & Tang 2009;Agrawal & Dongari 2011;Rana, Torrilhon & Struchtrup 2013;Singh, Dongari & Agrawal 2013;Akintunde & Petculescu 2014;Khalil, Garzó & Santos 2014;Rahimi & Struchtrup 2014;, and have also been applied to hypersonic flows (Agarwal et al 2001), for which a simplified set of conventional Burnett equations was recently proposed specifically for rarefied hypersonic flows (Zhao, Chen & Agarwal 2014).…”

Derivation of extended-OBurnett and super-OBurnett equations and their analytical solution to plane Poiseuille flow at non-zero Knudsen number

“…The improvement of manufacturing technology and computational capacity has led to increasing attention to the importance of rarefied gas flows in various practical applications such as high-speed hypersonic flows (Ivanov & Gimelshein 1998), miniaturized microchannel flows (Agrawal, Kushwaha & Jadhav 2020; Akhlaghi, Roohi & Stefanov 2023) and rarefied flow conditions (Akintunde & Petculescu 2014). In such flow situations, the Knudsen number (), which is the ratio of the mean free path () to the characteristic length scale (), plays a crucial role in governing the flow physics.…”