Abstract
One of the problems that developers of wing-in-ground-effect vehicles have to solve is related to necessity to reduce the power required for detaching the craft from water. An efficient way to facilitate takeoff consists of blowing air under the main wing of the craft from special engines. This mode of vehicle operation is often called power augmentation or, briefly, PAR. Power augmentation provides additional dynamic head to support the vehicle at small speed and alleviates hydrodynamic loads due to the impact of waves upon the structure of the craft. From the viewpoint of aerodynamics and hydrodynamics, the problem of power-augmented takeoff is extremely complicated. It features the interaction of turbulent jets with the vehicle and water surface, the resulting spray effects, and the transient motion of the vehicle. In what follows, only very simplified models of power-augmented flows will be considered for a lifting system moving very close to the underlying surface.
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Reference
Another argument exists in favor of this scheme based on some data showing that the magnitudes of drag, obtained in theory, are somewhat larger than the experimental ones.
This can be realized by deflectable or retractable plates.
For the practical situation of blowing turbulent jets this result does not hold because due to certain momentum losses related to jet impingement upon the ground, the decrease in the averaged jet velocity and the entrainment of the surrounding air causes an increase in the jet width in the downstream direction.
This case was considered by Gallington et al.
As designated earlier, A is the aspect ratio of the wing and S ep is the characteristic relative gap under the endplates.
Note that this and other quantities that may vary spanwise are assumed to be averaged in the lateral direction.
In fact, the same rate of leakage from under the endplates allow for different combinations of the width of the effective gap under the endplates, the wing’s aspect ratio and the relative ground clearance.
Based on a reentrant jet model.
Most of the practical foil families have analytical descriptions.
This is valid in a wide practical range of Strouhal numbers.
In the reentrant jet scheme the role of such a model parameter is played by the angle of inclination of the jet with respect to the downstream direction.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2000 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Rozhdestvensky, K.V. (2000). Schematized Flow Models for a Power-Augmented Lifting System. In: Aerodynamics of a Lifting System in Extreme Ground Effect. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-04240-3_8
Download citation
DOI: https://doi.org/10.1007/978-3-662-04240-3_8
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-08556-7
Online ISBN: 978-3-662-04240-3
eBook Packages: Springer Book Archive