The effects of aerodynamic perturbation forces on the orbital life of low altitude Low Earth Orbit (LEO) satellites are investigated, with a focus on the secular perturbations caused by lift and drag. The secular effects can be divided into the circularization of the orbit for both lift and drag perturbation forces, and the decrease of the orbit semimajor axis for drag perturbation. A study of ...

The classical problem of the fluid mechanics is the problem of a supersonic motion around a thin body was generalized to the case of non-equilibrium gas. The drag and lift force coefficients were founded. It is shown that the drag and lift force coefficients in the acoustically active supersonic flow are both decreased.

Flight is one of the energetically most costly activities in the animal kingdom, suggesting that natural selection should work to optimize flight performance. The similar size and flight speed of birds and bats may therefore suggest convergent aerodynamic performance; alternatively, flight performance could be restricted by phylogenetic constraints. We test which of these scenarios fit to two m...

AtReynolds numbers approaching those ofmicro air vehicles (both engineered and natural), the Eppler 387 airfoil (in common with many other smooth profiles) can have multiple lift and drag states at a single wing-incidence angle. Prestall hysteresis and abrupt switching between stable states result from sudden flow reattachment and the appearance of a large separation bubble. It is shown that co...

The aerodynamic characteristics of the wing-in-ground effect (WIG) craft model that has a noble configuration of a compound wing was experimentally investigated and Universiti Teknologi Malaysia (UTM) wind tunnel with and without endplates. Lift and drag forces, pitching moment coefficients, and the centre of pressure were measured with respect to the ground clearance and the wing angle of atta...

We examined the effects of aerodynamic forces on the mechanical power output of running insects for which kinematic data were available. Drag and lift on the cockroaches Periplaneta americana (a small, rapidly running species) and Blaberus discoidalis (a larger, more slowly moving species) were measured in a wind tunnel. Although lift would be expected to affect power output by altering functio...

The aerodynamic performance of a reduced-scale coaxial rigid rotor system in hover and steady forward flights was experimentally investigated to gain insights into the effect interference between upper lower rotors influences advance ratio, shaft tilt angle lift offset. featured by 2 m-diameter, four-bladed hingeless installed test rig. Experiments were conducted ?3.2 m wind tunnel at China Aer...