The background of schlieren technology

No matter what kind of aircraft, including stealth aircraft, flying in the air, they will cause violent disturbances in the relatively calm airflow, just like a high-speed speedboat speeding on the water and setting off a white wave. The disturbance of the airflow by the aircraft will form huge wake vortices, which will remain in the air for a long time. Therefore, there must be a period of time between takeoffs of passenger aircraft at the airport to allow the following aircraft to avoid the vortices of the preceding aircraft and avoid An accident occurred where the plane lost control.

The vortex of the aircraft is so huge and persistent that although it is invisible to the naked eye, in front of the schlieren camera, it is as clear as the waves passing on the calm water. Schlieren photography anti-stealth is based on this principle. Although the schlieren camera cannot see the stealth aircraft, it can clearly see the air vortex trajectory generated by the aircraft's flight. This vortex trajectory cannot be eliminated with existing technology. On the camera, it is as obvious as the exhaust cloud of the aircraft in the blue sky. No aircraft can escape the fate of being discovered.

Although stealth aircraft have performed many technical treatments on their exhaust, such as adding special chemicals to reduce the temperature of the wake, using special injection paths to quickly mix it with the surrounding air, etc. wait. By reducing the characteristics of infrared signals, it is difficult to detect.

However, what it cannot change is that the wake will heat the surrounding air, making the area where the aircraft flies over significantly warmer than the background sky temperature. Therefore, the schlieren camera is improved so that its working band is in the mid-to-far infrared band. In front of the infrared schlieren camera, the airflow trajectory disturbed by the stealth aircraft in the night sky is as obvious as the trajectory of meteors in the night sky, and stealth is impossible to talk about. .

If infrared schlieren cameras are combined with passive optical ranging technology, stealth aircraft can be effectively positioned. Multiple schlieren cameras can be connected into a monitoring network to continuously track stealth aircraft. , and guide your own aircraft and anti-aircraft missiles to destroy the stealth aircraft.