394
P. Liu
by a large contraction ratio and a multi-layer damping net installed in
the stable section.
(4) Variable density wind tunnel, in which the density of airflow can
be artificially changed to obtain different experimental Reynolds
numbers. One way to change the density of the air is to use the
gas denser than the air, such as nitrogen, as a wind tunnel medium.
Another method is to change the total pressure of the airflow, that is,
to increase the pressure of the wind tunnel.
(5) Tailspin wind tunnel is a special wind tunnel that studies the development and modification of aircraft tailspin by free flight. Most of these
wind tunnels are vertical wind tunnels. The test section is set vertically. The airflow direction in the test section is from down to up.
The airflow velocity at the center of the test section is about 5−10%
lower than that at the edge, that is, the velocity distribution on the
cross section of the test section is in a dish shape, so that the tailspin
model is kept near the center of the test section.
(6) Rafale wind tunnel, also known as a gust wind tunnel, is a kind of
special wind tunnel that produces artificial airflow simulating gust and
studies the ability of aircraft to adapt to natural gust in flight through
the model test. During the experiment, the model launcher throws
the model roughly horizontally and makes it pass through the vertical
airflow. The motion trajectory of the model is photographed with a
high-speed camera. The cross-sectional area of the vertical flow is large
and the velocity is not large (about less than 15 m/s). A gust wind
tunnel is relatively rare, the general wind tunnel after modification
can also carry out gust tests.
(7) Free-flying wind tunnel is a special wind tunnel that allows the model
to fly freely in the airflow of the test section. The low-speed free-flying
wind tunnel is usually blow-down, which is characterized by the fact
that the axis of the wind tunnel and the velocity of the airflow can be
adjusted rapidly to simulate various dynamic flight states. Models can
be powered or not. The deflection angle of the control surface of the
model is controlled by remote control outside the tunnel. High-speed
camera can be used to record the model during the experiment.
(8) Icing wind tunnel is a special wind tunnel that studies the
phenomenon of icing on the surface of aircraft body and ground
structures in flight and the methods to prevent or eliminate it. It is
characterized by a cooling device in front of the stability section and
a sprayer in the stability section, so that the icing conditions of the
prototype flow field can be simulated in the test section.
P. Liu
by a large contraction ratio and a multi-layer damping net installed in
the stable section.
(4) Variable density wind tunnel, in which the density of airflow can
be artificially changed to obtain different experimental Reynolds
numbers. One way to change the density of the air is to use the
gas denser than the air, such as nitrogen, as a wind tunnel medium.
Another method is to change the total pressure of the airflow, that is,
to increase the pressure of the wind tunnel.
(5) Tailspin wind tunnel is a special wind tunnel that studies the development and modification of aircraft tailspin by free flight. Most of these
wind tunnels are vertical wind tunnels. The test section is set vertically. The airflow direction in the test section is from down to up.
The airflow velocity at the center of the test section is about 5−10%
lower than that at the edge, that is, the velocity distribution on the
cross section of the test section is in a dish shape, so that the tailspin
model is kept near the center of the test section.
(6) Rafale wind tunnel, also known as a gust wind tunnel, is a kind of
special wind tunnel that produces artificial airflow simulating gust and
studies the ability of aircraft to adapt to natural gust in flight through
the model test. During the experiment, the model launcher throws
the model roughly horizontally and makes it pass through the vertical
airflow. The motion trajectory of the model is photographed with a
high-speed camera. The cross-sectional area of the vertical flow is large
and the velocity is not large (about less than 15 m/s). A gust wind
tunnel is relatively rare, the general wind tunnel after modification
can also carry out gust tests.
(7) Free-flying wind tunnel is a special wind tunnel that allows the model
to fly freely in the airflow of the test section. The low-speed free-flying
wind tunnel is usually blow-down, which is characterized by the fact
that the axis of the wind tunnel and the velocity of the airflow can be
adjusted rapidly to simulate various dynamic flight states. Models can
be powered or not. The deflection angle of the control surface of the
model is controlled by remote control outside the tunnel. High-speed
camera can be used to record the model during the experiment.
(8) Icing wind tunnel is a special wind tunnel that studies the
phenomenon of icing on the surface of aircraft body and ground
structures in flight and the methods to prevent or eliminate it. It is
characterized by a cooling device in front of the stability section and
a sprayer in the stability section, so that the icing conditions of the
prototype flow field can be simulated in the test section.