The ability of certain animal groups to fly by themselves has always stirred our imaginations. Even in the 15th century Leonardo da Vinci was famously inspired to try to build bird-like ornithopters. However, it was not until the 19th century that the nature of aerodynamic lift was understood, and it is a little more than 100 years since it was successfully applied to achieve flight by an aircr...

The present study provides a detailed description of the forces on an ellipsoidal particle in vicinity rough wall. Three-dimensional numerical simulations are performed using body-fitted mesh to estimate drag, lift, and torque coefficients. A large number conducted over range parameters, such as shear Reynolds ([Formula: see text]), orientation angle wall-particle separation distance get compre...

We show by computational solution of the incompressible Navier-Stokes equations with friction force boundary conditions, that the classical inviscid circulation theory by Kutta-Zhukovsky for lift of a wing and laminar viscous boundary layer theory by Prandtl for drag, which have dominated 20th century flight mechanics, do not correctly describe the real turbulent airflow around a wing. We show ...

electric vehicles (evs) have gained the attention of many authorities, automakers and researchers due to their considerable energy saving and emission reduction. one of the main issues that must be considered in design of a road vehicle is the calculation of aerodynamic forces. this issue also must be scrutinized in the design of evs. installation of rear spoiler is one of the solutions propose...

A Lagrangian-Eulerian numerical scheme for the investigation of bubble motion in turbulent flow is developed. The flow is analyzed in the Eulerian reference frame while the bubble motion is simulated in the Lagrangian one. Finite volume scheme is used, and SIMPLEC algorithm is utilized for the pressure and velocity linkage. The Reynolds stresses are modeled by the RSTM model of Launder. Upwind ...

The main aim of this study was to investigate the effect of finger spread on the propulsive force production in swimming using computational fluid dynamics. Computer tomography scans of an Olympic swimmer hand were conducted. This procedure involved three models of the hand with differing finger spreads: fingers closed together (no spread), fingers with a small (0.32 cm) spread, and fingers wit...

In the present study, multiple-fan active control wind tunnel tests are conducted to investigate aerodynamic forces on a 5:1 rectangular cylinder in sinusoidal streamwise winds with different angles of attack (AoA). The effects frequency, amplitude, and AoA flow statistical parameters, spectral characteristics, spanwise distributions drag, lift, moment coefficients analyzed. Results show that e...

This study involved a theoretical and an experimental investigation of the direct free kick in soccer. Our aim was to develop a mathematical model of the ball's flight incorporating aerodynamic lift and drag forces to explore this important 'set-play'. Trajectories derived from the model have been compared with those obtained from detailed video analysis of experimental kicks. Representative va...

The adjoint-based sensitivity analyses well explored in hydrodynamic stability studies are extended to calculate the sensitivity of forces acting on an aerofoil with respect to wall transpiration. The magnitude of the sensitivity quantifies the controllability of the force, and the distribution of the sensitivity represents a most effective control when the control magnitude is small enough. Si...

To improve knowledge of the wind loads on photovoltaic structures mounted on flat roofs at the high angles required in high latitudes, and to study starting flow on low aspect ratio wind turbine blades, a series of wind tunnel tests were undertaken. Thin flat plates of aspect ratios between 0.4 and 9.0 were mounted on a sensitive three-component instantaneous force and moment sensor. The Reynol...