CL, CD, CD0 = lift coefficient, drag coefficient, and drag coefficient with zero lift DSi = dynamic soaring number sample E, Emin = aircraft total energy and minimum sustainable total energy, J g = gravity acceleration, m∕s h, hmin = altitude and safety altitude, m K = drag-polar-induced drag gain k1, k2, k3 = necessary and sufficient conditions inequality parameters L, D = lift and drag forces...

During slow flight, bird species vary in their upstroke kinematics using either a 'flexed wing' or a distally supinated 'tip-reversal' upstroke. Two hypotheses have been presented concerning the function of the tip-reversal upstroke. The first is that this behavior is aerodynamically inactive and serves to minimize drag. The second is that the tip-reversal upstroke is capable of producing signi...

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...

in this paper, the effect of electric field on two-dimensional low reynolds air flow around an airfoil and variation of the forces acting on the airfoil is numerically investigated. the electric current and poisson’s equations are solved and the outcome is considered as a source term in the momentum equations. the energy equation is not considered due to its weak effect on the phenomena. the fi...

An analysis is performed to study the supersonic flow over conical bodies of three different cross sections circular, elliptic and squircle (square with rounded corners) shaped. Perturbation method is applied to find flow variables analytically. In order to find lift and drag forces the pressure force on the body is found, the component along x is drag and the component along z is lift. Three e...

Limpets are commonly found on wave-swept rocky shores, where they may be subjected to water velocities in excess of 20 m s(-1). These extreme flows can impose large forces (lift and drag), challenging the animal's ability to adhere to the substratum. It is commonly thought that the conical shape of limpet shells has evolved in part to reduce these hydrodynamic forces while providing a large ape...

The performance of a generic surfboard fin is investigated in a cavitation tunnel to gain basic understanding of the viscous flows involved for future systematic experimental and computational studies. Measurements of lift and drag forces, pitching moment and results of flow visualisation are presented. Surface flow visualisation studies reveal relatively complex boundary layer transition and s...

In this paper, three-dimensional two phase turbulent free surface flow is solved by an in-house code. The incompressible Reynolds average Navier-Stocks equations (RANS) with k-ε turbulence model are solved by the finite volume method in the non-orthogonal curvilinear coordinates. For the modeling of the free surface effect, Lagrangian propagation volume tracking method (VOF-PLIC) is used. The c...