![Table 4. Comparison of computational results and numerical study [20] for blowing and suction flow control.](/figures/table-4-comparison-of-computational-results-and-numerical-28tkial8.webp)
![Fig. 6. Comparison of computational results and numerical study [39] for suction flow control.](/figures/fig-6-comparison-of-computational-results-and-numerical-3r1et9zc.webp)
Q2. What are the future works in "Numerical study of blowing and suction slot geometry optimization on naca 0012 airfoil" ?
Further works are needed to investigate some essential suction/blowing parameters, including the number of slots, slot arrangements, and synthetic jet parameters.
Q3. What was the turbulence level used to match the wind tunnel characteristics?
A low free-stream turbulence level was used to match the wind tunnel characteristics, such that the stream turbulence intensity was selected as less than 0.1%.
Q4. What are the methods of flow control?
Methods of flow control to achieve transition delay, separation postponement, lift enhancement, drag reduction, turbulence augmentation, and noise suppression have been considered [2].
Q5. How much do the lift and drag coefficients decrease under perpendicular blowing?
When the jet width varied from 1.5% to 4% of the chord length, the lift and drag coefficients decreased by approximately 23% and 16%, respectively, under A = 0.5 and an angle of attack of 14°.
Q6. How does the lift coefficient increase with increasing jet width?
With increasing jet width, the lift coefficient increases continuously until a jet width of 2.5% of the chord length and then insignificantly decreases.
Q7. What is the effect of blowing jet width on the aerodynamic characteristics of a NACA?
Increasing blowing jet width improves the lift-to-drag ratio continuously for tangential blowing and reduces it constantly and quasilinearly for perpendicular blowing.
Q8. How does perpendicular blowing increase the lift-to-drag ratio?
perpendicular blowing decreases the lift-to-drag ratio before stall angle intensively and increases the aerodynamic characteristics after stall, for instance, perpendicular blowing increased the lift-to-drag ratio by 17.5% at an angle of attack of 18°.
Q9. What was the common method used to simulate the turbulent flow?
To simulate the turbulent flow, eddy or turbulent viscosity distribution was employed rather than the Reynolds stress tensor through eddy viscosity turbulent models, including algebraic or zero-equation models, one-equation models, and two-equation models.
Q10. What is the jet width for tangential blowing?
Jet widths of 3.5% and 4% of the chord length appear to be the most effective choice for tangential blowing at the airfoil trailing edge.
Q11. How much lift coefficient increases when blowing jet widths of 0.5 and 0.5?
Under an angle of attack of 14° and a blowing amplitude of 0.5, the lift coefficient increased to 1.157 and 1.163 for blowing jet widths of 1.5% and 4.0% of the chord length, respectively.
Q12. What is the effect of perpendicular blowing on the lift and drag coefficients?
With the use of perpendicular suction, not only the lift-to-drag ratio increases dramatically but also the stall angle delays effectively.
Q13. What is the effect of a smaller blowing jet width on the lift and drag coefficients?
the authors indicate that smaller blowing jet widths provide more positive effects for using perpendicular blowing to minimize drag and larger jet widths are effective to maximize it.
Q14. How much lift to drag is increased for perpendicular blowing?
The lift-to-drag ratio increased by approximately 17% for tangential blowing under H = 4%, A = 0.5, and Lj = 0.8C from the leading edge, with an angle of attack of 18°.
Q15. How many errors were recorded for lift and drag coefficients in the k- realizable?
the maximum errors for lift and drag coefficients in the k-ε realizable model at an angle of attack of 14° were 17% and 25%, respectively.
Q16. How does the lift coefficient change with jet width?
The lift-to-drag ratio increases continually up to jet widths of 3.5% to 4% of the chord length along with jet width and then decreases.
Q17. What is the effect of blowing jet width on aerodynamic coefficients?
As mentioned earlier, the blowing jet amplitude has an insignificant effect on aerodynamic coefficients and poses only a 2% increase in the lift-to-drag ratio.
Q18. What is the effect of jet width on the lift and drag coefficients?
The variations in lift and drag coefficients with jet width are almost negligible at low angles of attack, although they have shown significant changes with the increment of angle of attack.
Q19. How much did the lift-to-drag ratio increase under perpendicular blowing?
the lift-to drag ratio increased by 17% under a jet amplitude of 0.5, a jet width of 4% of the chord length, and an angle of attack of 18°.
Q20. What is the general heading of boundary layer control?
Techniques developed to manipulate the boundary layer, either to increase the lift or decrease the drag, are classified under the general heading ofboundary layer control or flow control [1].
Q21. What is the lift coefficient of tangential blowing?
12-14 present the lift, drag, and lift-to-drag ratio versus jet width with blowing jet amplitudes of 0.3 and 0.5 for tangential blowing at the trailing edge, respectively.
Q22. How was the interval size reduced for blowing and suction slots?
The interval size was reduced to 0.00125 for blowing and suction slots, as indicated in Fig. 4.The residuals in all simulations were continued until the lift and drag coefficients reach a full convergence.
Q23. When was the first experimental work on boundary layer suction for wings conducted?
The earliest known experimental works [4-6] on boundary layer suction for wings, primarily in the wind tunnel, were conducted in the late 1930s and the 1940s.
Q24. What is the effect of the tangential blowing jet width on the lift coefficient?
the variations of tangential blowing parameters have a remarkable effect on the lift coefficient and a marginal effect on the drag coefficient.