Ducted fans installed on vertical takeoff and landing vehicles experience significant ground effect during landing. The aerodynamic characteristics of a ducted fan hovering transitioning in the are studied using numerical simulations this paper. flowfields obtained by solving Reynolds Averaged Navier–Stokes equations with Multiple Reference Frame approach. When hovers effect, blade thrust incre...

This work presents a systematic approach to analyzing the aerodynamic characteristics of tandem rotor forward autorotation considering rotor-to-rotor interference. The single-rotor computational model trimmed from generic helicopter flight dynamics analysis program was used as baseline model. effectiveness is demonstrated by comparison with data wind tunnel tests performed in this work. disk an...

In this study, an unsteady aerodynamic simulation is performed to realize the influences of platform surge motion on the aerodynamic performance of a high capacity offshore floating wind turbine. A dynamic model with pitch angle control system is utilized to propose a more realistic model of wind turbine and also achieve the rated condition of the rotor. The transient effect of platform surge m...

The material properties of food can exert a significant influence on tooth morphology. Although the stiffness or toughness of a material is usually of prime concern, other aspects of material properties (such as extensibility) can be of equal importance. Previous experimental work on the effect blade shape has on fracturing biological materials indicated a notched blade greatly reduced the work...

The computational fluid dynamics method was used to simulate the flow field around a wind turbine at yaw angles of 0°, 15°, 30°, and 45°. angle attack relative velocity spanwise sections blade were extracted with reference points method. By analyzing pressure distribution characteristics surface, mechanism surface in yawed condition discussed. results showed that variations related azimuth radi...

OBJECTIVE Clip artifacts limit the visualization of intracranial structures in CT scans from patients after aneurysmal clipping with cobalt alloy clips. This study is to analyze the parameters influencing the degree of clip artifacts. METHODS Postoperative CT scans of 60 patients with straight cobalt alloy-clipped aneurysms were analyzed for the maximal diameter of white artifacts and the ang...

Abstract Until recently, horizontal-axial wind turbines with blades having a wing profile occupied predominant position in the world energy market. But currently, vertical-axial units are of increasing interest and this is understandable from point view their important features as: no requirements for orientation turbine to wind, possibility placing electrical other equipment on ground, changes...

A novel actuator disk model (ADM) coupled with lifting-line theory is proposed in this paper. Several virtual planform blades are placed on a plane constant azimuthal interval, and the applied to each blade predict effective angle of attack. The considers local lift drag forces acting surface cells by interpolating predicted attack various azimuth angles plane; therefore, individual tip vortice...

The angle and number of wind turbine blades. used for testing is a vertical Darrieus-H type with variations in the blades 2, 3, 4. Blades NACA 4415 specifications, speeds 4 m/s, 5 6 7 m/s s, 8 m/s. source using fan. Variations attack are 0o, 10o, 20o, 30o. blade made sea sengon wood. At position attack, 10o rotates faster due to influence lifting force 0o difficult rotate because straight direc...

In the current study, twin wind blades are designed, fabricated and the effect of various gap ratio (g*) at various angle of attacks (α) on a next to each other twin wind blades are examined in an open-channel wind tunnel. Aerodynamic forces and moments are determined by using three-constraint force balancer. For gap ratio of zero, the aerodynamic attributes are like those of a solitary wind bl...