Engineering topics

Chestnutt, D.

Publications and source records attributed to Chestnutt, D..

17 records

All sources NASA NTRS DOE OSTI

NASA NTRS1984

Flight effects on fan noise with static and wind-tunnel comparisons

Previously cited in issue 10, p. 1377, Accession no. A83-25910

Preisser, J. S.↗

NASA NTRS1983

Flight effects on fan noise with static and wind tunnel comparisons

A flight test program utilizing a JT15D-1 turbofan engine has been conducted with the objectives of studying flight effects on fan noise and evaluating the simulation effectiveness of both a wind tunnel and a static test configuration that incorporated an inlet control device (ICD). In conjunction with synchronized laser-radar tracking and meteorological profile information, data obtained from a linear array of ground microphones was narrowband-analyzed and ensemble-averaged to yield highly accurate far-field flight acoustic results. Utilizing appropriate corrections, flight, wind tunnel, and static acoustic data were normalized to a static-equivalent, 100-foot radius, lossless reference condition. Data comparisons showed that both the static test with ICD and wind tunnel were generally very effective in simulating flight blade-passage-frequency (BPF) noise levels. However, differences were observed in broadband noise levels and in the details of the multiple-pure-tone harmonics.

Preisser, J. S.↗

NASA NTRS1982

Flight effects of fan noise

Simulation of inflight fan noise and flight effects was discussed. The status of the overall program on the flight effects of fan noise was reviewed, and flight to static noise comparisons with the JT15D engine were displayed.

Chestnutt, D.↗

NASA NTRS1976

Survey of inlet noise reduction concepts for gas turbine engines

An overview is given of advanced concepts for the suppression of noise in the inlets of gas turbine engines. Inlet geometric and operating parameters are presented and design criteria for suppression methods are discussed. Noise suppression concepts are described, the directions of current research are reviewed. Problem areas requiring further work are indicated. Well established approaches to inlet noise reduction - namely, acoustic liners and high subsonic Mach number inlets which are the focus of considerable current research activity are considered along with the acoustic absorption and watet vapor injection.

Lansing, D. L.↗

NASA NTRS1976

Advanced inlet duct noise reduction concepts

A progress report is given on the implications of inlet noise reduction on aircraft direct operating costs (DOC). It considers treated inlet rings, various other inlet noise reduction concepts, and forward-speed effects. The report was limited to relatively well-established approaches to inlet noise reduction, such as acoustic liners and fixed-geometry/high-subsonic-speed inlets which are the focus of considerable current research activity. All of the concepts discussed are of a "passive" nature, i.e., no moving parts or electrical feedback systems.

Chestnutt, D.↗

NASA NTRS1976

Survey of inlet noise reduction concepts for gas turbine engines

This paper presents an overview of advanced concepts for the suppression of noise in the inlets of gas turbine engines. Noise suppression concepts are described, the directions of current research are reviewed, and problem areas requiring further work are indicated. The discussion focuses on acoustic liners, high Mach number inlets, active acoustic absorption, water vapor injection, and blade row reflection.

Lansing, D. L.↗

NASA NTRS1974

Variably positioned guide vanes for aerodynamic choking

A choking device to cause a sonic barrier to be formed which reduces the transmission of noise in a direction opposed to the direction of air flow in a compressor that may be part of an aircraft gas turbine engine is described. The noise reduction is accomplished by proper shaping and movement of inlet guide vanes, and an actuator is connected to selected guide vanes to effect movement by programmed amounts as required to choke or partially choke within the design range of the axial-flow-air compressor.

Chestnutt, D.↗

NASA NTRS1973

Air transportation noise technology overview

The NASA and DOT technology program planning for quieter air transportation systems is reviewed. To put this planning in context, the nature of the noise problem and the projected nature of the air transportation fleet are identified. The technology program planning reviewed here is discussed in relation to the following areas of activity: systems analysis, community acceptance, basic research and technology, and the various classes of civil aircraft, i.e. existing and advanced transports, powered-lift transports, and general aviation.

Maggin, B.↗

NASA NTRS1972

Noise control technology for jet-powered STOL vehicles.

Progress report on the problem of community noise control for jet-powered STOL aircraft. Noise goals are discussed, along with noise control approaches for meeting these goals. Such significant noise control factors as the basic engine cycle, engine-airframe integration varieties, and certain details of the lift augmentation system are given special attention.

Hubbard, H. H.↗

NASA NTRS1972

Flap noise generation and control

The characteristics of aerodynamic noise generated by the interaction of an airstream with a flap surface are discussed. The location and behavior of various noise sources were investigated to determine optimal quieting techniques. A schematic diagram of the jet-flap concepts being considered for integrated-powered-lift systems for short takeoff aircraft is shown. Each of the concepts has in common high velocity turbulent air flowing over relatively rigid surfaces with resultant production of interaction noise. The nature, location, and control of noise sources which involve the interactions of air flows with airfoil surfaces are examined.

Chestnutt, D.↗

NASA NTRS1971