Numerical simulation of 3-D flow around sounding rocket in the lower thermosphere

• Main Authors: J. Kurihara, K.-I. Oyama, N. Iwagami, T. Takahashi
• Format: Article
• Language: English
• Published: Copernicus Publications 2006-03-01
• Series: Annales Geophysicae
• Online Access: https://www.ann-geophys.net/24/89/2006/angeo-24-89-2006.pdf

Numerical simulations using the Direct Simulation Monte Carlo (DSMC) method are known to be useful for analyses of aerodynamic effects on in-situ rocket measurements in the lower thermosphere, but the DSMC analysis of a spin modulation caused by an asymmetric flow around the rocket spin axis has been restricted to the two-dimensional and axially symmetric simulations in actual sounding rocket experiments. This study provides a quantitative analysis of the spin modulation using a three-dimensional (3-D) simulation of the asymmetric flow with the DSMC method. Clear spin modulations in the lower thermospheric N₂ density measurement by a rocket-borne instrument are simulated using the rocket attitude and velocity, the simplified payload structure, and the approximated atmospheric conditions. Comparison between the observed and simulated spin modulations show a very good agreement within 5% at around 100km. The results of the simulation are used to correct the spin modulations and derive the absolute densities in the background atmosphere.