Analysis of weather balloon data to evaluate the aerodynamic influence on the launch phase of SHEFEX II

In this work, an advanced atmospheric model (IATM) for the flight of SHEFEX II is created and its effect on the aerodynamic loads of the first-stage fins of SHEFEX II is investigated. The atmospheric model bases on weather balloon data collected at the starting day of the flight experiment. The wind data are filtered using empirical mode decomposition (EMD) and reduced by their intrinsic mode functions (IMF) to get wind data without balloon oscillation. Compared to a linear interpolated atmosphere (LATM), the numerical results show no significant influence on the forced motion body loads but there is a high impact of wind on the fins of SHEFEX II as unsteady simulations show an increase up to over 50% of dynamic loading, while viscous effects can be neglected.