National Research Council, Aeronautical Report LR 

About: National Research Council, Aeronautical Report LR is an academic journal. The journal publishes majorly in the area(s): Wind tunnel & Mach number. Over the lifetime, 141 publications have been published receiving 693 citations.

Numerical solutions of the flow field for conical bodies in a supersonic stream

Abstract: : A numerical procedure for solving the problem of steady supersonic inviscid flow around smooth conical bodies is presented. Results are obtained by solving the elliptic partial differential equations that define the conical flow between the body and the shock. Results are given for circular cones up to moderately high relative incidences, including some cases for incidences beyond a critical value at which the entropy singularity moves from the surface. Also presented are a few results for elliptic cones at zero and non-zero incidence, as well as results for another conical body whose cross section is defined by a fourth order even cosine Fourier series. The applicability of the method can be limited by the entropy singularity moving too far away from the surface by the flow field containing regions of locally conically supersonic flow, or by the shock wave approaching very close to the Mach wave. Comparison of results shows excellent agreement with other theoretical methods and also with experimental results. The method is efficient in computer time.

On the adhesion of ice to various materials

Abstract: Tests were made on a centrifugal apparatus to assess the adhesion of droplet impact ice oa various aircraft structural materials and possible low adhesion coating materials. The results indicate that this type of ice exhibits considerably lower adhesion strength than normal ice. When Teflon is used as the test surface this effect is evidently nullified on account of droplet penetration into the pores in the surface of the material . This confirms earlier observations that Teflon does not exhibit " ice-phobic" properties to droplet impact ice.

Analysis of the flow past a shockless lifting airfoil in design and off-design conditions

Abstract: A shockless lifting airfoil designed for shockless inviscid flow at M∞ = 0. 75 with CL = 0. 63 was tested at high Reynolds numbers up to 27 X 10σ in design and off-design conditions. The experimental results are compared against theoretical results, showing in general good agreement.

Nonlinear flutter of a circular cylindrical shell in supersonic flow

Abstract: A nonlinear analysis is presented for calculating the limiting amplitudes of cylindrical shell flutter using a four-mode approximation for the shell deflection. The aerodynamic pressure is approximated by linear piston theory, and the nonlinearity enters the problem through the nonlinear shallow shell equations for the cylinder. The governing equations are reduced to four modal equations by applying Galerkin's method, and limit cycle solutions are obtained by both the method of harmonic balance and by numerical integration. Two types of limit cycle flutter were obtained: (a) two-mode standing wave flutter, and (b) four-mode circumferentially traveling wave flutter. The theory indicates that the traveling wave type of flutter can occur at aerodynamic pressures below the linear flutter boundary.

An investigation of the near noise fields of a choked axisymmetric air jet

Abstract: An experimental investigation was completed of the near sound field of a choked axisymmetric air jet of 2.25-in diameter. The results include surveys of tbe sound pres sure levels in the area surrounding the jet and the identification of various screech frequencies. A schlieren system with stroboscopic spark synchronisation was used to photograph an axisymmetric mode and a spiralling mode of the jet oscillations.