Laminar-flow airfoils

Axial-Flow Compressors 283 Laminar-Flow Airfoils... 

In contrast, stabilization of boundary layer by contouring the airfoil surface to achieve favourable pressure gradient as a passive way is found to be practical and attractive. The resultant section is known as the Natural Laminar Flow (NLF) airfoil and this is an area which has been under renewed investigation over the last three decades. Early efforts of designing... 

Fujino, M., Yoshizaki, Y. and Kawamura, Y. (2003). Natural-laminar-flow airfoil development for a lightweight business jet. J. of Aircraft, 40(4), 609-615. 

Jacobs, E.N. (1939). Preliminary report on laminar-flow airfoils and new methods adopted for airfoil and boundary layer investigations. NACA WR L-345. 

Viken, J.K. (1983). Aerodynamic design considerations and theoriti-cal results for a high Reynolds number natural laminar flow airfoil. M.S. Thesis. The School of Engineering and Applied Science, George Washington Univ, USA. 

Airfoil. This is another very effective design characteristic. The airfoil is located below the sash at the fi ont of the counter top. Air flows between the airfoil and the counter top, creating a laminar flow across the counter to the rear baffle slot, effectively sweeping the top clear of fumes. 

Figure 5 Boundary layer separation Turbulent vs. laminar boundary flow close to an airfoil. Source From Ref. 89.

The primary cause of decreased efficiency at low Reynolds numbers is a laminar separation of the flow from the airfoil surface. This leads to a phenomenon known as a laminar separation bubble. The shape of the airfoil and pressure distribution have a significant impact on the location and size of the separation bubble, and so design and testing of airfoils can dramatically improve MAV performance. 

Transonic Airfoil Flow. The transonic flow around a DRA2303 airfoil [9] was chosen as the aerodynamic reference case to discuss the efficiency and quality of the zonal RANS-LES method compared to a pure LES method. The flow field is defined by M = 0.72, Rtc — 2.6 10 based on the chord length c, and the angle of attack 0 = 3°. The laminar-turbulent transition is fixed at the pressure and suction side of the airfoil at x/c = 0.05 for both numerical configurations by introducing a wall surface roughness of an amplitude of approximately 10 inner wall units or 8 IQ Ay/c. 

---