Aerofoil
An aerofoil component ( 32 ) defining an in use leading edge ( 38 ) and a trailing edge ( 40 ). At least one of the leading edge and the trailing edge ( 38, 40 ) comprises a plurality of first and second recesses ( 52, 56 ) projecting in a direction corresponding with an in use flow direction, the first and second recesses being spaced apart normal to the in use flow direction and having a different chordal extent.
1. An aerofoil component comprising:
a leading edge; and
a trailing edge, at least one of the leading edge and the trailing edge defining a waveform profile, the waveform profile extending in a spanwise direction of the aerofoil component, and the waveform profile including a superposition of a first wave and a second wave, the first wave and the second wave each having a different wavelength such that the waveform profile defines a plurality of first and second recesses spaced in the spanwise direction of the aerofoil component, the plurality of first and second recesses of the waveform profile extending in a chordwise direction of the aerofoil component, each of the plurality of first recesses having a different depth than a depth of each of the plurality of second recesses in the chordwise direction, the plurality of first recesses being located forward of a mean chord line of the waveform profile in the chordwise direction and the plurality of second recesses being located rearward of the mean chord line of the waveform profile in the chordwise direction.
2. The component according to claim 1 , wherein is the plurality of first recesses are each separated in the spanwise direction by at least one second recess of the plurality of second recesses.
3. The component according to claim 1 , wherein the first wave and the second wave have equal amplitudes.
4. The component according to claim 1 , wherein the waveform profile is defined by
c
(
r
)
=
C
0
+
h
1
cos
(
2
π
r
γ
1
)
+
h
2
cos
(
2
π
r
γ
2
)
where c(r) is representative of a chordwise extent c of the leading edge or the trailing edge from the mean chord line C 0 as a function of a span r, h 1 and h 2 are representative of the amplitude of the first wave and the second wave respectively, and γ 1 and γ 2 are representative of the wavelength of the first wave and the second wave.
5. The component according to claim 4 , wherein γ 1 /γ 2 is between ½ and 2.
6. The component according to claim 4 , wherein h/c 0 is between 1/10 and ⅙.
7. The component according to claim 1 , wherein an aerofoil cross sectional profile of an aerofoil varies across a span of the aerofoil in accordance with a formula:
y
(
x
,
r
)
=
{
f
(
x
/
c
0
)
,
0
<
x
/
c
0
<
2
/
3
,
f
(
x
/
c
(
r
)
)
,
2
/
3
≤
x
/
c
(
r
)
≤
1
where y is representative of a thickness of the aerofoil at chordwise position x and spanwise position r, and f(x) defines the aerofoil cross sectional profile, and wherein x=0 is defined as the trailing edge, and x=1 is defined as the leading edge.
8. The component according to claim 1 , wherein the aerofoil component is an aerofoil of a gas turbine engine.
9. The component according to claim 8 , wherein the aerofoil is an outlet guide vane of the gas turbine engine.
10. A gas turbine engine comprising the component according to claim 1 .
11. An aircraft comprising the gas turbine engine according to claim 10 .
12. A method of designing an aerofoil component, the method comprising steps of:
defining a first wave and a second wave, the first wave having a different wavelength to the second wave;
superposing the first wave and the second wave to define a superposed waveform; and
defining an aerofoil having a leading edge profile or a trailing edge profile including the superposed waveform such that the leading edge profile or the trailing edge profile defines a plurality of first and second recesses spaced in the spanwise direction of the aerofoil component, the plurality of first and second recesses of the waveform profile extending in a chordwise direction of the aerofoil component, each of the plurality of first recesses having a different depth than a depth of each of the plurality of second recesses in the chordwise direction, the plurality of first recesses being located forward of a mean chord line of the waveform profile in the chordwise direction and the plurality of second recesses being located rearward of the mean chord line of the waveform profile in the chordwise direction.