Base passive porosity for vehicle drag reduction
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsSteven X. S. Bauer, Richard M. Wood
Life of this patent
Estimating the term…
Abstract
A device for controlling drag on a ground vehicle. The device consists of a porous skin or skins mounted on the trailing surface and/or aft portions of the ground vehicle. The porous skin is separated from the vehicle surface by a distance of at least the thickness of the porous skin. Alternately, the trailing surface, sides, and/or top surfaces of the ground vehicle may be porous. The device minimizes the strength of the separation in the base and wake regions of the ground vehicle, thus reducing drag.
Claims24
A drag reduction device for use on a ground vehicle, comprising:
- a porous outer surface attached to the aft portion of a ground vehicle;
- a substantially solid inner surface;
- said porous outer surface comprising a first portion and at least one second portion:
- said first portion being attached to a trailing surface of the ground vehicle;
- said at least one second portion being attached to at least one side of said ground vehicle;
- and
- said porous outer surface and said substantially solid inner surfaces being separated from and substantially parallel to one another to form a space therebetween, such that the porous outer surface acts as a means for permitting the entrance and exit of air into and out of said space, whereby the asymmetric character of the external trailing wake flow field of the ground vehicle is changed to a substantially steady and laterally symmetric trailing wake flow field.
A drag reduction device for a ground vehicle, comprising:
- a porous outer surface on the aft portion of a ground vehicle;
- a substantially solid inner surface;
- said porous outer surface comprising a first portion and at least one second portion;
- said first portion forming a trailing surface of the around vehicle;
- said at least one second portion forming at least a portion of at least one side of said ground vehicle:
- and
- said porous outer surface and said substantially solid inner surfaces being separated from and substantially parallel to one another to form a plenum therebetween, such that the porous outer surface acts as a means for permitting the entrance and exit of air into and out of said plenum, whereby the asymmetric character of the external trailing wake flow field of the ground vehicle is altered such that drag is reduced.
A method for reducing drag of a ground vehicle comprising the steps of:
- attaching a porous outer surface to the aft portion of a ground vehicle;
- said porous outer surface comprising a first portion and at least one second portion;
- said first portion being attached to a trailing surface of the ground vehicle, and
- said at least one second portion being attached to at least one side of said ground vehicle;
- aligning said porous outer surface with a corresponding substantially solid inner surface;
- and
- positioning said porous outer surface and said corresponding substantially solid inner surfaces separated from and substantially parallel to one another to form a space therebetween, such that the porous outer surface acts as a means for permitting the entrance and exit of air into and out of said space, whereby the asymmetric character of the external trailing wake flow field of the ground vehicle is changed to a substantially steady and laterally symmetric trailing wake flow field.
A method for reducing drag of a ground vehicle comprising the steps of:
- perforating the outer surface of the aft portion of a ground vehicle to produce a porous outer surface;
- said porous outer surface comprising a first portion and at least one second portion;
- said first potion forming a trailing surface of the ground vehicle, and
- said at least one second portion forming at least a portion of at least one side of said ground vehicle;
- aligning said porous outer surface with a corresponding substantially solid inner surface;
- and
- positioning said porous outer surface and said corresponding substantially solid inner surfaces separated from and substantially parallel to one another to form a space therebetween, such that the porous outer surface acts as a means for permitting the entrance and exit of air into and out of said space, whereby the asymmetric character of the external trailing wake flow field of the ground vehicle is changed to a substantially steady and laterally symmetric trailing wake flow field.
Dependencies are inferred from the claim text.