This paper investigates the effects of nonlinear large deflection bending on the aerodynamic performance and aeroelasticity of a high aspect ratio flexible wing. A nonlinear large deflection theory is developed for aeroelasticity to account for large deflection bending. An analysis is conducted to compare the nonlinear bending theory with the linear bending theory. The results show that the non...

Adaptive closed-loop control is used to optimize the lift-to-drag ratio of post-stall separated flow over a NACA 0025 airfoil using multiple amplitudemodulated (AM) or burst-modulated (BM), zero-net-mass-flux (ZNMF) actuators that cover the central 33% span of the airfoil. A simplex optimization approach uses the lift and drag measured by a strain-gauge balance for feedback and searches for the...

Numerical investigation of flow around a square cylinder are presented using the multi-relaxation-time lattice Boltzmann methods at different Reynolds numbers. A detail analysis are given in terms of time-trace analysis of drag and lift coefficients, power spectra analysis of lift coefficient, vorticity contours visualizations, streamlines and phase diagrams. A number of physical quantities mea...

In many cases, a set of obstacles, such as bridge piers and abutments, are located in the river waterway. Bridge piers disrupt river’s normal flow, and the created turbulence and disturbance causes diversion of flow lines and creates rotational flow. Geometric shape and position of the piers with respect to flow direction and also number of piers and their spacing are effective on changing the ...

Many flying animals use both flapping and gliding flight as part of their routine behaviour. These two kinematic patterns impose conflicting requirements on wing design for aerodynamic efficiency and, in the absence of extreme morphing, wings cannot be optimised for both flight modes. In gliding flight, the wing experiences uniform incident flow and the optimal shape is a high aspect ratio wing...

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...

A method is described for measuring the effective lift: drag ratio of a bird in napping flight from the bird's span ratio; that is, the ratio of the wing span in the upstroke to that in the downstroke. The method depends on the assumptions that the circulation on the wing is constant, and that the lift varies in proportion to the span. With some simplifications, it can be applied in the field t...

Tests have been made at a Mach number of 4.03 and Reynolds number of 3'4 million on two families of models, consisting of delta wings with underslung half-Cone bodies. The wing sweepback angles were 75 ° and 80 °, and the appropriate cone semi-vertex angles tested were 4 °, 10 ° and 13 ° for the larger wing and 4 °, 6"7 ° and 10 ° for the smaller wing. The surface distributions were measured at...

When blood components (e.g., leukocytes and platelets) adhere to a surface (e.g., blood vessel wall), shear flow causes the elongation of the non-adherent part of the cell membrane forming a long thin cylinder shape (i.e., cell tether). The formation of cell tether is important for regulation of cell adhesion strength and stabilization of cell rolling, and may significantly affect the flow dyna...

We newly introduce lift force into the aerodynamics of dust grains in a protoplanetary disk. Although many authors have investigated the effects of the drag force, gravitational force, and electric force on the dust grains, the lift force has never been considered as a force exerted on dust grains in a gas disk. We show in this paper that the dust grains can be continuously spinning as a result...