Flow visualization tests are performed when flow characteristics on the model are needed to be determined and displayed. Flat black model is generally preferred to avoid glare and obtain good quality image. This provides better results from the tests. Flow characteristics and aerodynamic incompatibilities are investigated during the tests. Pressure sensitive paint system, smoke, oil and tuft method can be used in AWT to visualize flow characteristics. Pressure sensitive paint method basically consists of embedding luminescence molecules which are sensitive to the oxygen pressure in a specially produced polymer-made oxygen-permeable paint, coating the model surface with this paint and stimulating it by light source (Laser, ultraviolet lamp, xenon lamp, LED) at the appropriate wavelength. AWT is the only wind tunnel having pressure-sensitive paint system in Turkey. Since PSP method is a non-invasive method, measuring the pressure values becomes possible without causing any disturbance in the flow. Painting the test model with PSP paint and the application of oven curing processes are carried out by a certified technician. Integration and development efforts are being carried out for the operational use of PSP method in tests.
Smoke flow visualization is carried out using the Dantec smoke generation machine in the tunnel. Regional examinations can be made by placing the smoke in the desired location of the test model. In the tuft method, tufts attached to the model surface enable the streamlines to be displayed. Tufts are produced with the tuft preparation bench in the tunnel and attached on the model by hand. 80 number transmission oil is used in flow visualization tests. It is aimed to achieve its consistency by mixing the oil with kaolin clay. Oil should be dense enough not to flow from the surface of the model and thin enough to adapt to flow movements. Testing can also be done by painting different parts of the test model (such as nose, body, wing or fin) with different types of oils. However, before the procedure, test conditions and model suitability should be evaluated with the customer. Using flow visualization tests, flow direction determination on model surface, flow separation, noise sources, cockpit windows and ventilation systems in various civil and military systems have been performed.