Method for forming an add-on component for an aerofoil
AssigneeBrunel University London
InventorsTze Pei Chong, Philip Charles Woodhead
Life of this patent
Estimating the term…
Abstract
A method is provided for forming an add-on component for an aerofoil which enable the structure of the aerofoil to be tuned in order to reduce the amplitude of sound produced at frequency fpeak when air flows in a flow direction from the leading edge over the trailing edge of an aerofoil. The method applies both to add-on components having a slitted formation and a Double-Rooted Trailing Edge Serration (abbreviated to “DRooTES”).
Claims20
A method for forming an add-on component for an aerofoil having a leading edge and a trailing edge, said component being formed in order to reduce the amplitude of sound produced at frequency fpeak when air flows in a flow direction from the leading edge of the aerofoil over the trailing edge of the component at a freestream velocity U∞, the method including the steps of:
- (a) selecting a frequency fpeak of sound that is to be reduced;
- (b) selecting a freestream velocity U∞ of air;
- (c) providing a component having a joining edge for joining to a trailing edge of an aerofoil and a trailing edge opposite said joining edge;
- (d) forming the trailing edge of the component into a plurality of pairs of peaks, each of said pairs having a first trough, a first peak, a second trough, a second peak, which is a greater distance from the joining edge than the first peak, and a third trough, wherein the first trough is on one side of the first peak, the second trough is between the first and second peak, and the third trough is on the other side of the second peak to the second trough;
- (e) wherein the first and third troughs of each pair of peaks lie substantially on a first axis, the second troughs of each pair of peaks lie substantially on a second axis, and the second peaks of each pair of peaks lie on a third axis;
- (f) and wherein the component is formed according to the formula:
- h
- ′
- =
- c
- ˆ
- ·
- U
- ∞
- ·
- κ
- 2
-
- f
- p
-
- e
-
- a
-
- k
- ,
- where d′ is from 0.4 to 0.8 and
- κ
- =
- (
- h
- ′′
- h
- ′
- )
- 0
- .
- 4
- where h′ is the shortest distance between the first axis and the second axis, h″ is the shortest distance between the 2nd and 3rd axis, fpeak is the frequency of sound to be reduced and U∞ is the freestream velocity in the flow direction of air flowing over the trailing edge of the component.
A method for forming an add-on component for an aerofoil having a leading edge and a trailing edge, said component being formed in order to reduce the amplitude of sound produced at frequency fpeak when air flows in a flow direction from the leading edge of the aerofoil over the trailing edge of the component at freestream velocity U∞, the method including the steps of:
- (a) selecting a frequency fpeak of sound that is to be reduced;
- (b) selecting a freestream velocity U∞ of air;
- (c) providing a component having a joining edge for joining to a trailing edge of an aerofoil and a trailing edge opposite said joining edge;
- (d) forming the trailing edge of the component into a plurality of peaks separated by troughs with each peak being connected to each trough on either side of the peak by a wall which is substantially perpendicular to the trailing edge, wherein the peaks each have a width (a) which is substantially parallel to the trailing edge and the troughs each have a width (W) which is substantially parallel to the trailing edge, said width also being the gap between adjacent peaks, wherein the peaks lie substantially on a first axis and the troughs lie substantially on a second axis and wherein the shortest distance from the first axis to the second axis is defined as H,
- (e) and wherein the component is formed according to the formula:
- H
- =
- c
- ˆ
- ·
- U
- ∞
- 2
-
- f
- p
-
- e
-
- a
-
- k
- ,
- where ĉ is from 0.4 to 0.8.
Dependencies are inferred from the claim text.