Breakdown of supersonic airflow in an engine intake
Schlieren flow visualization showing unstart of axisymmetric intake at Mach 2. Unstarted shock structure evident on left, started intake on right.
In supersonic aerodynamics, an unstart refers to a generally violent breakdown of the supersonic airflow. The phenomenon occurs when mass flow rate changes significantly within a duct. Avoiding unstarts is a key objective in the design of the engine air intakes of supersonic aircraft that cruise at speeds in excess of Mach 2.2.
In supersonic aerodynamics, an unstart refers to a generally violent breakdown of the supersonic airflow. The phenomenon occurs when mass flow rate changes...
is decelerated. Examples: In supersonic propulsion: ramjet, scramjet, unstart. In flow control: needle valve, choked venturi. In this case the gas ahead...
with a fully fueled D-21, on a planned checkout flight, suffered from an unstart of the drone after its separation, causing it to collide with the M-21...
cause the shock wave to be expelled from the intake. This is known as an unstart. Some air inlets feature a biconic centrebody (MIG-21) to form two conic...
traveling upstream into the inlet. If that were to happen, the engine may unstart, resulting in loss of thrust, among other problems. To prevent this, scramjet...
compression process, i.e. through systems of multiple shocks. During an 'unstart' the efficient shock system would be replaced by a very inefficient single...
Other problems operating a supersonic wind tunnel include: starting and unstart of the test section (related to maintaining at least a minimum pressure...
contraction ratio was assessed, and it was shown to be applicable for the hard unstart/restart configurations. Curran, E. T.; Murthy, S. N. B. (2001). "7 "Scramjet...
wave in the throat suddenly moving forward beyond the lip, known as inlet unstart. Spillage drag is high and pressure recovery low with only a plane shock...
airframes, as the high energy pulsing of the engine can cause the inlet to unstart and stop the reaction, in addition to putting high stress on the nacelle...
Kantrowitz limit to predict the restart contraction ratio was assessed, and it was shown to be applicable for the hard unstart/restart configurations....
sufficient heat to power the aircraft without thermally choking the flow (and unstarting the engine) the combustor has to grow and the amount of heat added grows...
Whitney J58 used a mixed compression inlet, a configuration sensitive to unstarts, ie shock expulsion giving an external bow shock-wave. Catamaran boats...
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