Abstract
The supersonic mixing layer formed on the surface of hypersonic/supersonic flight vehicles’ optical windows is the main structure that induces aero-optical effects (AOEs), which may cause severe imaging degradation. Previous research has found that the ramp vortex generator array (RVGA) with a height of 1 mm can suppress the AOE of a
M
c
=
0.17
supersonic mixing layer. In this paper, three RVGAs with different heights are considered. The nano-tracer-based planar laser scattering technique and ray tracing method are applied to do the aero-optical analysis. The root mean square of the optical path difference (
O
P
D
r
m
s
), Strehl ratio (SR), imaging displacement (ID), and angle deviation (AD) are taken as evaluation parameters. It is found that a smaller aperture size (
A
D
) corresponds to a better SR in the aperture size range of
5
m
m
∼
100
m
m
. Then a beam with an incident angle
α
=
15
∘
and a 15 mm
A
D
is used to study the influence of RVGA’s height on suppressing the AOE. When the RVGA is applied, the
I
D
¯
and
A
D
¯
(overline means time-averaged results) in different sections of the supersonic mixing layer are significantly normalized, which can simplify the AOE’s correction procedure. The higher the RVGA is, the more the
O
P
D
r
m
s
¯
is reduced and the weaker the AOE is. RVGA1 (
h
=
1.2
m
m
) has the best performance in suppression of the AOE because it introduces much more disturbance than RVGA2 (
h
=
1.0
m
m
) and RVGA3 (
h
=
0.5
m
m
) and achieves better inhibition of the formation and development of the K-H vortices and more reduction of the whole thickness of the supersonic mixing layer.
Funder
National Defense Basic Scientific Research Program of China
Natural Science Foundation of Hunan Province
National Natural Science Foundation of China
Subject
Atomic and Molecular Physics, and Optics,Engineering (miscellaneous),Electrical and Electronic Engineering