An optimisation procedure coupled with computational fluid dynamics (CFD) is proposed to minimise the aerodynamic drag and to improve the static and dynamic stabilities of generic rounds at supersonic speeds (Mach 1·5 to 4). First, the Active-set algorithm, Sequential Quadratic Programming (SQP) is used as the optimisation method for drag minimisation. The objective function is the zero-lift drag computed from a semi-empirical solution. The constraints are based on the geometric restrictions of the body. CFD is then employed to validate the accuracy of the drag prediction from the semi-empirical solution and to incorporate the stability requirements into the optimisation process. A supersonic round body is considered as an example application. The optimised body provides up to 15% drag reduction and 46% increase in gyroscopic stability while remaining dynamically stable over the whole range of the operating Mach numbers.

No abstract

No abstract

This paper addresses the fundamental aerodynamics, stability, and control analysis of a solar power Unmanned Aerial Vehicle (UAV) as a part of the preliminary design stage. The tactical solar-powered UAV addressed in this paper is primarily developed for intelligence, surveillance, and reconnaissance (ISR) missions at low altitude. Moreover, such design also has a dual-use capability, which could be utilized in both military and civilian domains. The aerodynamic characteristics of the UAV are obtained from both computational fluid dynamics analysis technique and the wind-tunnel testing at the design operating Reynolds number ranging from 1x105 – 4.5x105. The fundamental aerodynamics coefficient consists of lift, drag, and pitching moment variations versus the angle of attack. The stability and control analysis was carried out based on the small disturbance theory in correlation with the XFLR5 software. The results show that the tactical solar power UAV design could achieve high aerodynamic efficiency at a 4-degree angle of attack which is corresponding to the lift-to-drag ratio of 20.05. Also, the analysis results confirm that the design possesses positive static and dynamic stability at the design cruise flight condition.

No abstract