Search NASA⌕ Search

Engineering topics

Spaid, F. W.

Publications and source records attributed to Spaid, F. W..

10 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

An experimental study of transonic flow about a supercritical airfoil

A series of experiments was conducted on flow fields about two airfoil models whose sections are slight modifications of the original Whitcomb supercritical airfoil section. Data obtained include surface static-pressure distributions, far-wake surveys, oil-flow photographs, pitot-pressure surveys in the viscous regions, and holographic interferograms. These data were obtained for different combinations of lift coefficient and free-stream Mach number, which included both subcritical cases and flows with upper-surface shock waves. The availability of both pitot-pressure data and density data from interferograms allowed determination of flow-field properties in the vicinity of the trailing edge and in the wake without recourse to any assumptions about the local static pressure. The data show that significant static-pressure gradients normal to viscous layers exist in this region, and that they persist to approximately 10% chord downstream of the trailing edge. Comparisons are made between measured boundary-layer properties and results from boundary-layer computations that employed measured static-pressure distributions, as well as comparisons between data and results of airfoil flow-field computations.

Spaid, F. W.↗
NASA NTRS1983

An experimental study of transonic flow about a supercritical airfoil. Static pressure and drag data obtained from tests of a supercritical airfoil and an NACA 0012 airfoil at transonic speeds, supplement

Surface static-pressure and drag data obtained from tests of two slightly modified versions of the original NASA Whitcomb airfoil and a model of the NACA 0012 airfoil section are presented. Data for the supercritical airfoil were obtained for a free-stream Mach number range of 0.5 to 0.9, and a chord Reynolds number range of 2 x 10 to the 6th power to 4 x 10 to the 6th power. The NACA 0012 airfoil was tested at a constant chord Reynolds number of 2 x 10 to the 6th power and a free-stream Mach number range of 0.6 to 0.8.

Spaid, F. W.↗
NASA NTRS1981

Measurements of the boundary layer and near wake of a supercritical airfoil at cruise conditions

The flow behavior within the upper-surface boundary layer and near wake of a supercritical airfoil operating at cruise conditions is discussed. Experimental results obtained from wind-tunnel tests are presented which provide a more detailed description of the flow in these regions than was previously available. Mean streamwise velocity profiles measured by pitot-pressure-probe and laser-velocimeter techniques were found to be in excellent agreement. Other mean-flow properties obtained by the laser-velocimeter technique were the local flow angles in the viscous layers and the static pressures at the edges of the boundary layer and wake. The data set also includes measurements of the turbulence intensity and turbulent Reynolds-stress distributions as obtained by the laser-velocimeter technique. To assess the effects of the shock wave, a less extensive set of measurements was realized at a subcritical test condition. The two test conditions (Mach number at free-stream conditions = 0.72, airfoil section lift coefficient = 0.76 and Mach number of free-stream conditions = 0.5, airfoil section lift coefficient = 0.75) provide a good test for state-of-the-art prediction methods because the upper-surface-boundary layer is separated just upstream of the trailing edge in both cases.

Johnson, D. A.↗
NASA NTRS1975

Detailed transonic flow field measurements about a supercritical airfoil section

The transonic flow field about a Whitcomb-type supercritical airfoil profile was measured in detail. In addition to the usual surface pressure distributions and wake surveys, schlieren photographs were taken and velocity vector profiles were determined in the upper surface boundary layer and in the near wake. Spanwise variations in the measured pressures were also determined. The data are analyzed with the aid of an inviscid transonic finite-difference computer program as well as with boundary layer modeling and calculation schemes.

Hurley, F. X.↗
NASA NTRS1975

Supercritical airfoil flowfield measurements

Detailed measurements in the transonic flowfield about a Whitcomb-type supercritical airfoil profile are presented including surface pressure distributions, far wake surveys, spark schlieren photographs, and a series of vector velocity profiles in the boundary layer and in the near wake. A flowfield composite for the transonic drag rise condition is constructed from these data. The boundary layer measurements are compared with current correlation and computation schemes, and the importance of viscous thickening effects is demonstrated by the results of wave drag rise calculations for the thickened and unthickened profiles.

Hurley, F. X.↗
NASA NTRS1975

Miniature probe for transonic flow direction measurements

A miniature probe is developed for measuring flow direction in one plane as well as stagnation pressure in the boundary layer and near wake of a transonic airfoil. The probe tip geometry and calibration curves are given, along with near wake survey data obtained for a supercritical airfoil. The advantages of the probe are ruggedness, ease of fabrication, ability to measure flow direction at a point, and insensitivity to out-of-plane velocity components.

Spaid, F. W.↗