Abstract:
Improvement in terminal accuracy is an important objective for future artillery
projectiles. Generally, it is often associated with range extension and precision. This
paper deals with the research of aerodynamic characteristics of anti-aircraft artillery
and medium tank projectiles. In Bangladesh, a very little study is available for
determining the aerodynamic characteristics of projectiles which are used in the
Bangladesh army. When a projectile is launched it experiences a drag force which
is more than the gravitational force due to the supersonic speed of the projectile.
Aerodynamic characteristics are strictly related and will affect the stability of the
projectiles, thus it is vital to obtain reliable aerodynamic characteristics estimation
to carry out a good design of projectile. In this study, a set of a hollow projectile is
considered since it shows good performance characteristics and it is easy to
handle. For our research we have considered two types of anti-aircraft artillery
projectiles, i.e. 57 mm & 37 mm and 125 mm medium tank projectile. Both
experimental and numerical studies have been done on this type of projectiles. In
this study, the main emphasis is given to determine the pressure coefficient, Drag
coefficients, lift coefficient, and the behavior pattern of the projectiles at different
angles of attack. To study the aerodynamic characteristics of the projectiles the
experiment is conducted in an open circuit subsonic wind tunnel available at MIST
where uniform flow velocity (4.7m/s) is maintained across the flow direction. For the
experiment, the angle of attack is varied between 30° to 50° is considered with an
interval of 5°. Here inclined manometer was used to find out the surface static
pressure and then the pressure coefficient was determined from that. Finally, for
the numerical scheme, the ANSYS Software was used to simulate the experiment.
In this study, it was found that the drag and lift forces acting on the projectiles,
increase with the increase in the size. In some cases, the drag and lift forces
increase by more than 80%. The drag and lift forces also increased when the angle
of attack increases. However, it was found that the rate of increasing the lift forces
is higher (45%) than the drag forces for a case.
