α angle of attack, rad Γ circulation, m2s−1 λ wake wavelength, m ρ∞ free-stream air density, kgm −3 τ panel tangential vector ω angular velocity, rad s−1 a non-dimensional distance between aerofoil mid-chord and centre of rotation A panel area, m b semi-chord, m ∆b panel span, m B wingspan, m c aerofoil chord, m ∆c panel chord, m C Theodorsen’s function, C(k) = F (k) + iG(k) Cd sectional drag c...

Aerodynamic drag force breakdown of a typical transport aircraft shows that lift-induced drag can amount to as much as 40% of total drag at cruise conditions and 80-90% of the total drag in take-off configuration. One way of reducing lift-induced drag is by using wing-tip devices. By applying several types of winglets, which are already used on commercial airplanes, we study their influence on ...

Abstract The aerodynamic characteristics of NACA4412 airfoil with different pitching motion elements were compared and analyzed based on CFD in this research. results are acquired as follows: the difference between lift drag coefficients during pitch up down motions becomes larger increase amplitude or initial angle attack; increases, coefficient grows slightly greater much greater; attack slig...

We describe a computationally efficient simulation-driven design methodology for single-element airfoils at high-lift conditions. Direct optimization of an accurate but computationally expensive high-fidelity simulation model based on Reynolds-Averaged Navier-Stokes equations is replaced by iterative updating and re-optimization of a cheap surrogate. The surrogate model exploits a low-fidelity ...

A procedure for tailoring a blended wing-body con guration to reduce its computed wave drag is described. The method utilizes an iterative algorithm within the framework of rst-order linear theory. Four computed examples are included. In each case, the zero-lift wave drag was reduced without an increase in drag due to lift. Introduction In the initial rough-cut state of supersonic conguration d...

Abstract Studying the effect of leading-edge parameters 30P30N on aerodynamic characteristic was carried out. Effect changing gap and overlap slat airfoil were mainly investigated. Numerical simulation applied to obtain characteristics, results show that: lift coefficient in linear segment basically does not change with gap, drag decreases gap. The have obvious lift-to-drag ratio. smaller betwe...

Nylon (PA) netting is widely used in purse seines and other fishing gears due to its high strength and good sinking performance. However, hydrodynamic properties of nylon netting of different characteristics are poorly understood. This study investigated hydrodynamic characteristics of nylon netting of different knot types and solidity ratios under different attack angles and flow velocities. I...

1. Abstract This paper deals with the optimization of shape of aerodynamic profiles. The objective is to reduce the drag coefficient on a given airfoil while preserving the lift coefficient within acceptable ranges. A set of control points defining the geometry are passed and parameterized as a B-Spline curve. These points are modified automatically by means of CFD analysis. A given shape is de...