Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 64
Book Description
Methods for Assessing Wall Interference in the 2- by 2-foot Adaptive-wall Wind Tunnel
Author: A Two-Dimensional Adaptive-Wall Test Section with Ventilated Walls in the Ames 2- By 2-Foot Transonic Wind Tunnel
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781722151133
Category :
Languages : en
Pages : 64
Book Description
The first tests conducted in the adaptive-wall test section of the Ames Research Center's 2- by 2-Foot Transonic Wind Tunnel are described. A procedure was demonstrated for reducing wall interference in transonic flow past a two-dimensional airfoil by actively controlling flow through the slotted walls of the test section. Flow through the walls was controlled by adjusting pressures in compartments of plenums above and below the test section. Wall interference was assessed by measuring (with a laser velocimeter) velocity distributions along a contour surrounding the model, and then checking those measurements for their compatibility with free-air far-field boundary conditions. Plenum pressures for minimum wall interference were determined from empirical influence coefficients. An NACA 0012 airfoil was tested at angles of attach of 0 and 2, and at Mach numbers between 0.70 and 0.85. In all cases the wall-setting procedure greatly reduced wall interference. Wall interference, however, was never completely eliminated, primarily because the effect of plenum pressure changes on the velocities along the contour could not be accurately predicted. Schairer, Edward T. and Lee, George and Mcdevitt, T. Kevin Ames Research Center...
Adaptive-Wall Wind-Tunnel Investigations
Author: J. C Erickson (Jr)Publisher:
ISBN:
Category :
Languages : en
Pages : 83
Book Description
The results of a program of research on transonic wind tunnels with adaptive walls for eliminating wall interference are presented. A description is given of related experimental research performed at other laboratories using several alternative methods for controlling the flow. Features of the segmented- plenum, perforated-wall, two-dimensional test section of the Calspan One-Foot Tunnel and the associated instrumentation for measuring the flow disturbance quantities are reviewed and necessary modifications made to the original experimental configuration are described. Details of adaptive-wall iteration experiments with a 4%-blockage NACA 0012 airfoil model are presented, particularly those at a free-stream Mach number of 0.9 and nominal angles of attack of 3, 2 and 1 deg. In these experiments, regions of supercritical flow terminated by shock waves extended to the tunnel walls. The results of the experiments indicate that successful iterations toward interference-free flow conditions are achieved. For another phase of the research, conceptual design studies of a three-dimensional transonic adaptive-wall test section using the segmented-plenum, perforated-wall method of flow control are reported. Finally, numerical simulations of low-speed flow within the Calspan test section, including the interaction of the transpired boundary layer at the walls with the flow over the model, are described in AIAA Paper No. 81-0160, which is appended to the report.
Wind Tunnel Wall Interference (January 1980-May 1988)
Author: Marie H. TuttlePublisher:
ISBN:
Category : Interference (Aerodynamics)
Languages : en
Pages : 96
Book Description
Residual Interference Assessment in Adaptive Wall Wind Tunnels
Author: Scientific and Technical Aerospace Reports
Author: Research on Adaptive Wall Wind Tunnels
Author: Robert J. VidalPublisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 70
Book Description
The objective of this research was to investigate the utility of the Calspan self-correcting wind tunnel for minimizing or eliminating wall interference effects in two-dimensional transonic flows when shock waves from the test model extend to the tunnel walls. This report summarizes the experimental research performed with two-dimensional airfoils in the Calspan self-correcting wind tunnel and the theoretical research accomplished in support of the experiments. The experiments were performed with airfoil models having 4% and 6% solid blockage. The initial experiments with the 6%-blockage model were devoted to determining a practical mode of operation when shock waves from the model extend to the wall. The most practical model is to use wall control to obtain the desired distribution of longitudinal velocity components for subcritical walls. The Mach number is then increased and the wall control is readjusted, sequentially, until the desired test condition is achieved. At the high Mach numbers of interest, however, the available wall control was limited locally, and tunnel system changes were required. A method is reported for analyzing self-correcting wind tunnels with porous walls.
A Two-dimensional Adaptive-wall Test Section with Ventilated Walls in the Ames 2- by 2-foot Transonic Wind Tunnel
Author: Aerodynamics And Aeroacoustics - Proceedings Of The Symposium
Author: Fung K YPublisher: World Scientific
ISBN: 9814551570
Category :
Languages : en
Pages : 384
Book Description
The aim of the symposium was to gather fellow researchers, colleagues and friends of Professor William R Sears, a member of the National Academy of Science and the Academy of Engineering, on the occasion of his 80th birthday. Professor Sears is a leader in Aerospace Science and Aerodynamics research and the symposium was held in honour of his work in these areas.The symposium focussed on four areas in aeronautical science in which Professor Sears has made major contributions. These are wing design, unsteady aerodynamics and separation, aeroacoustics and self-correcting wind tunnels.
Two-dimensional Wind Tunnel Wall Interference
Author: M. MokryPublisher:
ISBN: 9789283514633
Category : Aerodynamics
Languages : en
Pages : 186
Book Description
A description and analysis is presented of the more important developments during the past decade in the understanding of the wall interference problem associated with two-dimensional wind tunnel testing at subsonic and transonic speeds. Discussed are: wall boundary conditions; asymptotic analysis of wall interference; classical and extended wall interference theories; wall interference corrections from boundary measurements; integral equation formulation of subcritical wall interference; and effects of side wall boundary layer on two-dimensional tests. Unsteady wall interference at subsonic flow conditions is reviewed. Recent advances in the adaptive wall technique, which actively reduces or eliminates wall interference, are also described. (Author).