Essential ingredients of a method for low Reynolds-number airfoils

Abstract

A calculation method for low-Reynolds-number flows is described and appraised in terms of comparisons between calculations and measurements. It comprises interaction between solutions of inviscid-and boundarylayer equations and involves the e n method to determine the location of the onset of transition with further interaction to insure that upstream effects of the turbulent-flow region are correctly represented. The importance of the length of the transition region, which usually occurs within a separation bubble, is demonstrated, and an extended version of the intermittency expression used in the Cebeci-Smith algebraic, eddy-viscosity formulation is proposed and shown to represent the separation-induced transitional flows. The comparison of calculated and measured results encompasses five airfoils, chord Reynolds numbers from 3 x 10 5 to 8 X10 6 , and angles of attack from 0-11 deg, and shows that the essential features of these flows are correctly represented.

Critical considerations in the mitigation of insect residue contamination on aircraft surfaces – A review

“…Through wind tunnel and flight testing, a number of empirical formulations and transition prediction methods have been established, although a model which incorporates all variables is not yet available. Research tools currently used to predict transition include the Linear Stability Theory (e n method), parabolised stability equations (PSE) and Direct Numerical Simulation (DNS); however, these are limited and are not frequently used to predict the effect of isolated roughness [29][30][31][32][33]. Other complex models, developed by experimentalists, can be found in references [34][35][36][37][38][39][40], and will not be detailed here.…”

Feasibility study of power generation using a turbine mounted in aircraft wing

“…Hence obtaining the results of power generation, aerodynamic efficiency, fuel efficiency leads to further investigation [4]. The study from various researchers states that there is a reduction in the boundary layer interaction because of the flow separations over the novel wing where the rotation of the blade takes place in the anticlockwise direction hence increase in the velocity at the upper surface of the wing [4] [5] [14]. The variation of the velocities for the different angle of attack over the slotted rotor wing are detailed in this work.…”

“…A systematic experimental test has been carried out to understand the influence of velocity flow at different angles of attack over the novel wing [5] [20]. Hence obtaining the results of power generation, aerodynamic efficiency, fuel efficiency leads to further investigation [4]. The study from various researchers states that there is a reduction in the boundary layer interaction because of the flow separations over the novel wing where the rotation of the blade takes place in the anticlockwise direction hence increase in the velocity at the upper surface of the wing [4] [5] [14].…”

“…60 sewing threads [1] [18]. Surface tufts only give data about the surface flows in the lowest part of the boundary layer [4]. Encapsulating the surface patterns to visualize the free stream flow over the model takes some skills and knowledge.…”

Aerodynamic Study of Airfoils with Leading Edge Imperfections at Low Reynolds Number

“…Therefore the initial objective of this research is to determine the level of degradation in the aerodynamic characteristics at low Reynolds numbers [1][2][3][4][5][6] of these imperfections in the manufacture, and determine whether there may be a value for which it would not be necessary to correct them.…”