Airfoil Behavior: Pressure Distribution over a Clark Y-14 Wing

Overview

Source: David Guo, College of Engineering, Technology, and Aeronautics (CETA), Southern New Hampshire University (SNHU), Manchester, New Hampshire

An airfoil is a 2-dimensional wing section that represents critical wing performance characteristics. The pressure distribution and lift coefficient are important parameters that characterize the behavior of airfoils. The pressure distribution is directly related to the lift generated by airfoils. A Clark Y-14 airfoil, which is used in this demonstration, has a thickness of 14% and is flat on the lower surface from 30% of chord length to the back.

Here we will demonstrate how the pressure distribution around an airfoil is measured using a wind tunnel. A Clark Y-14 airfoil model with 19 pressure ports is used to collect pressure data, which is used to estimate the lift coefficient.

Procedure

Remove top cover of test section to install the Clark Y-14 model (chord length, c = 3.5 in). The test section should be 1 ft x 1 ft and the wind tunnel should be able to sustain a maximum airspeed of 140 mph.
Mount the aluminum Clark Y-14 model on the turntable inside the test section so that port #1 is facing upstream. Replace top cover. Note that the model is touching both the floor and the ceiling of the wind tunnel test section so no 3D flow around the airfoil develops.
Connect the 19 pressure tubes labeled 1 -

Results

The results of the lab are shown in Table 1 and Table 2. The data is plotted in Figure 3, which shows the pressure coefficient, C_p, versus the pressure port coordinate, x/c, for angles of attack at 0, 4, and 8°. To be more visually intuitive, the negative C_p values are plotted above the horizontal axis. This is to show that the upper surface (the top line of the chart) is mostly negative pr

Application and Summary

Pressure distributions on airfoils are directly related to lift generation and important information to characterize the performance of airfoils. Airfoil designers manipulate pressure distributions to acquire desired characteristics of airfoils. As such, pressure distribution information is the foundation of aerodynamics analysis during aircraft development.

In this experiment, the pressure distribution of Clark Y-14 was investigated in a wind tunnel and the 19 ports of pressure measurement we