Numerical simulation and formula fitting of aerodynamic drag force of stratosphere airship

A stratosphere airship with cylindrical sections in its middle was taken as a research object, the influence of fins, slenderness ratio, height and Re on aerodynamic drag force were studied by the verification of simulation method. Based on the parameter analysis, the estimating formula of aerodynamic drag coefficients under horizontal conditions was obtained using TableCurve3D software. What is more, a modified formula considering attack angles was also presented. The study demonstrates that mean wind-pressure coefficients decrease along the hull head, keep stable in the middle cylindrical section, and increase along the tail section. The curvature inflections of pressure-coefficients curves appear near the junctions of different sections. The contributive value of fins and hull to aerodynamic drag coefficients increases with the increase of attack angles, but hull is the main contributor. As the slenderness ratio or height increases, the aerodynamic drag coefficient decreases first and then increases. A decrease trend is presented with the increase of Re (1.0×10⁷~2.0×10⁸).