Due to growing concerns of authentication and security in the world, biometric security systems are becoming increasingly popular. Fingerprints tend to be the most used biometric feature in most security and identification system. In any fingerprint identification system, enhancement of the fingerprint image prior to recognition is essential. A fingerprint is an impression left by the friction ...

We derive an integral formula for the skin-friction coefficient of compressible boundary layers by extending Elnahhas and Johnson [“On enhancement layer skin friction turbulence: An angular momentum approach,” J. Fluid Mech. 940, A36 (2022)] incompressible layers. The is decomposed into sum contributions laminar coefficient, change dynamic viscosity with temperature, Favre–Reynolds stresses, me...

The decompositions of the skin-friction and heat transfer coefficients based on two-fold repeated integration in hypersonic transitional turbulent boundary layers are analyzed to explain generations wall skin friction transfer. Reynolds analogy factor slightly increases as temperature decreases, especially for extremely cooled wall. integral analysis is applied overshoot behaviours layers. coef...

We study different flow control methods on turbulent around a NACA4412 airfoil, using resolved large-eddy simulation (LES). find that changes in total skin friction due to blowing and suction are not very sensitive pressure-gradient conditions nor the Reynolds number. However, boundary-layer thickness, intensity of wall-normal convection, fluctuations much more affected, mostly adverse-pressure...