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The U.S. Air Force (USAF) atmospheric interceptor technology (ait) program must conduct protected species monitoring during periods immediately before and after ait rocket launches from the Kodiak Launch Complex. Monitoring and mitigation efforts for two protected species, the endangered Steller sea lion (Eumetopias jubatus) and the threatened Steller's eider (Polysticta stelleri), are a condition of the FONSI for the program and were conducted by the University of Alaska's Environment and Natural Resources Institute (ENRI) in the days before and after the ait-2 launch. The study reported herein was conducted from 12-15 September, 1999, before, during, and immediately after the ait-2 launch on 15 September. It ran in parallel with the ENRI effort and was designed to provide the USAF with detailed information about the acoustic characteristics of the ait-2 launch, in part for future prediction of animal impacts and in part for comparison with RNOISE model outputs. Opportunistic observations of animal behaviors were obtained during this effort as well. Larson-Davis sound monitors (LD 820, 824) were deployed to collect noise data automatically at four sites within the Safety Exclusion Zone (SEZ) for the launch, including two sites on Narrow Cape, the portion of Kodiak Island extending closest to Ugak Spit. A fifth monitor on Ugak Spit failed. A real-time DAT recording was collected just outside the SEZ, close to the Launch Control Complex (LCC). HSWRI and AFSMC cooperators were able to count and observe the behavior of marine mammals on 9/12 from Narrow Cape using a Meade ETX-9OEC Telescope (Lang 2000). They also collected behavioral observations during helicopter approaches and landings on Ugak Island 9/14 (2000-2130 hours) and 9/15 (1330-1350 hours). Sea lions were observed at Ugak Spit after the launch from 1345 to 1500 hours on 9/15 using the Meade telescope. There were no Steller's eiders in the area at the time of the launch. (6 tables, 12 figures, 20 refs.) 7, The original document contains color images. All DTIC reproductions will be in black and white. Prepared in collaboration with the Alaska Aerospace Development Corporation, the University of Alaska's Environment and Natural Resources Institute, and Wyle Laboratories.

Acoustic oscillations were induced in a sub-scale liquid rocket engine that burned liquid oxygen and gaseous hydrogen as propellants. The oscillations in the chamber were forced by a rotating gear just downstream of the nozzle throat. High frequency data was acquired for pressure and velocity via a pressure transducer and a magnetic flowmeter. The magnetic flowmeter obtains the acoustic gas velocity by measuring the voltage induced by the ionized combustion products moving through an externally imposed magnetic field. A cross correlation was performed on the velocity and pressure signals to determine the amplitude and phase difference of the two signals.

File characteristics: Database (11 files).Physical description: 1 CD-ROM disc. System requirements: DBASE IV files or Microsoft Access or both. To satisfy the Army's need for realistic safe limits for heavy weapon noise while wearing hearing protection, a 2 1/2 year study was undertaken. Using active duty military volunteers, 64 subjects established that the auditory system could be adequately protected with the RACAL muff from one to three exposures of the reverberant waveforms obtained from a rocket launcher out of an enclosure. Thus, nonauditory considerations set the exposure limits for this type of waveform

This report discusses possible approaches to the detection and location of artillery rockets by acoustic techniques. The acoustic signal is composed of rocket motor initiator noise, rocket motor burning noise, and ballistic wave noise. An acoustic model is applied to some test results. Distant detection of launched artillery rockets was found to be possible under conditions of low ambient noise. The location accuracy depends on the distance between the source and the detector, as well as on meteorological conditions. In locating the launch point, one must be able to distinguish between the rocket motor initiation noise from the launch point and the ballistic wave noise produced by the rocket in flight. Methods to improve the accuracy of location are suggested. Projections made for a foreign artillery rocket (140-mm, 3,500-lb thrust motor) show that detection in calm weather is possible to a range of 10 km from the launch point. Beyond 4 km, improved techniques are needed for locating the launch point with an error less than 200 m. Seismic and other related signals generated near launch should be investigated for use as a complementary tool to improve location accuracy.

The objective of the present research work is an understanding of the physical mechanisms by which energy is exchanged between the mean and acoustic flow fields in resonant combustion chambers (in particular, solid rocket motors). These processes may alter the balance between sources and sinks of oscillatory energy in the combustor significantly and thus are critical to our ability to predict the stability characteristics of proposed motor designs. The present report concentrates on the description and analysis of the computational results obtained to date in the study of acoustic refraction and flow turning phenomena. Three studies were conducted. The time-dependent compressible Navier Stokes equations were solved utilizing an implicit, non-iterative Linearized Block Implicit scheme. In the first study acoustic wave propagation in a tube with a coexisting sheared mean flow was investigated. The results demonstrate that acoustic refraction effects, i.e., the growth of acoustic pressure near the wall (for downstream propagation), are significant., In addition, the results demonstrate acoustic energy transfer to the mean flow as well as Richardson's annular effect. To the best of the authors' knowledge these are the first solutions demonstrating either Richardson's annular effect or refraction effects that are obtained through solution of the complete Navier-Stokes equations.

Supersedes PAT-APPL-643 562-75.

A community noise survey was conducted at Vandenberg AFB CA, from April 1984 to April 1985 at the request of the base bioenvironmental engineer for a baseline noise evaluation of Vandenberg AFB and the adjacent populated and unpopulated land areas. The purpose of the survey was to support planned environmental assessments for noise impact of the expected Space Transportation System (STS) launches and other missile launch activities at Vandenberg AFB. One year of community noise measurements were obtained in and around Vandenburg AFB with repeated monitoring of representative locations to characterize the impact Vandenberg AFB operations have on the noise environment. Measurement locations were chosen to include major noise sources, areas with special or historical interest, populated and unpopulated areas, and locations near to those where previous noise studies were performed. This report presents an initial analytical summary of the daily records for three of the most useful metrics measured: day-night average sound level (Ldn), community noise equivalent level (CNEL), and equivalent sound level (Leq).

This document contains expanded abstracts from the 1982 meeting on the Air Force basic research program on energy conversion relating to rocket propulsion. The meeting (Lancaster, CA on 2-4 March 1982) presented research supported by both the Air Force Office of Scientific Research and the Air Force Rocket Propulsion Laboratory. Major topics included: diagnostics of reacting flows, combustion, chemical kinetics, thermal properties, propulsion concepts, energetic materials, material and propellant ingredients, exhaust plumes, transition to detonation, combustion stability, structural mechanics. (Author)

In investigations of acoustic radiation from supersonic nozzles the greatest interest is presented by that part of the acoustic energy that relates to the bottom cross section of the central body of the annular jet, since this has an adverse effect on the constructional elements of the rocket apparatus and apparatus close to the bottom cross section. Therefore, this part of the acoustic radiation was studied., Edited trans. of Akademiya Nauk URSR, Kiev. Dopovidi. Seriya A: Fiziko-Tekhnichni ta Matematichni Nauki, n5 p471-474 1972.

SEE ALSO Part 1, AD0130793

See also Part 4, AD0254671.

Maximum sound pressure levels averaging 115 decibels, with extreme values of 90 and 128 decibels, were measured about one mile behind the Nike Zeus Missile Launcher for the variety of meteorological conditions occurring during four monthly tests.Additional small samples of data taken both near the launcher and at two miles distnce from the sound source suggest a 20-decibel decline in peak noise level per mile. The decay of the noise level following peak was between two and three decibels per second for the first ten seconds. A frequency analysis of the sound level measured at launch indicates that frequencies below 125 cps are predominant. Under mos meteorological conditions, the sound pressure levels at one mile behind the launcher would not be great enough to cause any structural damage or personnel injury. The levels would be above 90 decibels however, which approach the level at which complaints of annoyance become frequent. (Author)

The stress in aircraft structure resulting from multi-mode response to sonic excitation in resolved into an alternating stress component superimposed upon a slowly varying mean stress component. It is then found that the probability distribution of those components is nearly independent of the number of modes participating in the response. This finding could have considerable application in simplifying fatigue analysis and testing if it may be shown that the mean stress component has only low order effects upon fatigue life. Some of the possible applications are presented. A test program for establishing the significance of the mean stress component is outlined.

The objective of the procedure is to determine the effects of simulated or actual flight acoustics (high level noises) upon the missile skin, structure and components.

Study was made of forcing functions and their characteristics, methods of estimating a combined response, and proof tests required to qualify structure and equipment. The report is presented in three parts. Part One discusses the various sources of vibratory energy which can result in vehicle vibration including rocket noise, aerodynamic pressure fluctuations, wind shear and gust, meteorites and direct mechanical coupling. Part Two discusses the prediction of vibratory response through both empirical and analytical approaches, and includes a thorough discussion of the single degree of freedom system, resonance-on-resonance, panels, shells, mobility, generalized force, joint acceptance, correlations and other statistical tools. Part Three contains a discussion of fatigue and malfunction, the properties of an ideal test, implications of and methods for obtaining a simplified composite response and an examination of various test equivalences.

Possible sources of noise in space vehicles are reviewed. Information is summarized describing the various fluctuating pressure fields that may exist at the vehicle exterior. The response of the vehicle structure to these pressure fields and the resulting radiation of noise to the internal spaces are studied analytically. The need for new theoretical and experimental knowledge in specific areas is emphasized. The effects of rocket engine noise on communication and hearing are considered in detail. General comments are made concerning vehicle and equipment design for noise control., See also Volume 1, AD0205776.

Analytical and experimental studies have been made to examine the feasibility of using acoustic scale models for near field noise investigations. Analyses show that the important characteristics of noise generation, propagation, and measurement can be scaled. A few deviations from this involve small errors which are negligible in the near field. The most straightforward model duplicates the gas flow parameters of the full scale engine. The validity of such models has been demonstrated by a series of tests for a wide variety of nozzle exit conditions, from turbojet through rocket exhausts, and whether in a free field or in the presence of objects which interfere with the flow, such as shaped nozzles and flame deflectors. It is further determined both analytically and experimentally that models may be simplified without impairing the results of a scaled test. Considerations in simplifying a model include: reduction of the nozzle size; absence or presence of reflecting surfaces; use of fewer than the full scale number of engines; and use of a substitute gas which is different from and at a lower temperature than that in the full scale engine.

The feasibility of a compact instrument to measure the accumulated acoustic exposure of a flight vehicle is considered. The output data of the instrument will aid the estimation of fatigue life. A study of the conditions and parameters involved together with general requirements of the instrument is presented. Design criteria are discussed such as techniques for amplitude analysis, sampling and accumulation of data in a directly readable and usable form. A specific design of a breadboard model of the sonic recorder is given with test and performance data under laboratory conditions. A discussion of the effects of temperature, vibration, and power supply variations is also included. Complete circuit diagrams are provided.

High-frequency radar observations of nonburning rockets traversing the ionosphere often yield large range-discrete echoes and ionospheric path perturbations during periods in which the venting of fuel components or fluid ballast takes place. A study of several missile launchings during which such releases occurred has been conducted, and an analysis of the experimental data which takes into account the propagation conditions surrounding each launching is presented.

The feasibility of using helium jets as a practical substitute for actual rockets in scale model acoustic tests was investigated by conducting an experimental program with four heated helium models. Sufficient evidence is presented to indicate that the substitute gas modeling concept is valid, i.e., simulation of rocket noise can be achieved if the essential rocket flow parameters are duplicated. It is not possible to duplicate all flow parameters simultaneously and retain the essential feature of simplicity; compromises must be made. The helium model per formed best. This evaluation is based on agree ment in sound pressure levels with a small solid propellant rocket. An investigation was made to determine the effect of flight vehicle motion on propulsion system noise propagated to parts of the vehicle located in the near field. Ex periments were performed using a 0.6-in. diam eter heated air jet operating in a 16-in. diam eter acoustically-treated wind tunnel. Experi mental results compare favorably with predic tions based on the hypothesis which explains the effect of vehicle motion by two separate factors: the noise produced by a jet in motion depends on the relative velocity between the jet and the air through which it moves; and a shifting of the noise radiation pattern toward the rear occurs because of combined effects of vehicle motion and the finite velocity of sound., Report on Dynamic Problems in Flight Vehicles.

A technique for determining the impact point of missiles by the detection of the shock wave generated during a missile's descent was developed. This technique, including the instrumentation and computations involved and an error analysis, is presented. (Author)

An experimental acoustic survey was conducted inside two fiberglas missile nose cones in a simulated noise field at two intensities and two distances from the noise source. Data indicated an effect of geometric shape on spectral distribution and internal standing waves near the forward part of the nose cone. Empirical methods of computing transmission loss through the nose cone were unsatisfactory for determining sound levels within the nose cone. (Author)

An over-all view is presented of the acoustic noise-control pro blem. The following noise source characteristics and methods of noise control are discussed: specification of a noise source, aircraft propellers and reciprocating engines, aircraft jet and rocket engines, fluid flow devices, industrial machine noise, physical characteristics of miscellaneous environmental noise, general noise-control planning, noise-control requirements, control of structure-borne noise, control of air-borne noise, rooms and special enclosures, and evaluation of sound-control installations.

The investigation was conducted to determine the feasibility of launching missiles and superboosters from overwater sites. Information is needed to predict the depth of liquid-propellant rocket engine exhaust gas penetration into water. Methods will be required to minimize the depth of blast penetration and the upward splash of water. Since these large vehicles will generate high levels of noise during static test firing or lift-off, some method of noise suppression is desired in order to control possible harmful conditions for working personnel and to limit the size of the required test or launch area. Overwater blast tests with small-scale rocket engines of 250-, 500-, and 1000-lb thrusts were conducted (a) without underwater devices, (b) with underwater screens, and (c) with an underwater deflecting device exhausting into a group of cylindrical screens. Based on the results of this study, the following conclusions are believed warranted: (a) The rocket engine exhaust blast-penetration tests show that a relation exists between height of engine above the water, engine thrust, and depth of blast penetration into the water. (b) Depth of blast penetration can be reduced by an underwater deflecting device. (c) Splash action and noise intensity can be reduced by the use of an underwater deflector which directs the exhaust into a number of horizontal concentric, cylindrical screens. (Author)

This document covers the prediction of the HiBEX vibration, shock, and acoustic environments, the equipment flight certification test program, and the in-flight vibration measurements correlated to predictions. A method of analysis for transient data is presented. Test philosophy for a transient vibration environment with attendant high accelerations is discussed. (Author)

Measurements have been made of the acoustic losses in a resonator with a small vent, and their dependence on the speed of steady flow through the system and on the position of the vent. The resonator is a closed circular cylinder, resonant in the fundamental planewave mode, with a vent through the wall near the center. Steady gas flow is introduced at one end through a slightly porous piston whose vibration also generates sound. Losses are determined from the rate of decay of pressure. Significant flow-dependent loss attributable to the vent is found for flow speeds in the vent exceeding about 0.02 times the sound speed. The loss depends on vent position. Good quantitative prediction of this loss, at flow velocities above a critical value, can be made from a theory based on the characteristics of quasisteady fluid efflux from an orifice (total pressure quadratic in total flow). (Author)

A comprehensive technique for determining the magnitude of potential launch hazards is developed as an intermediate step in the process of selecting optimum launch sites for very high-thrust booster engines. Three characteristic launch site hazards are considered: acoustics, explosions, and toxicity. The siting criterial developed are generally applicable to most potential launch sites. In order to illustrate the site selection procedure a hypothetical three stage launch vehicle (9 million pounds thrust), and a prospective launch area with realistic environmental conditions are postulated. The resulting hazard estimates are employed to specify a particular launch complex location and configuration, and to establish launching constraints imposed by the assumed environment. Several field surveys are found necessary to provide critical data about potential launch sites for the assessment of hazards. Two of these, an acoustical measurement program and gas release tests, are described. (Author)

Contents: Concepts for aeroelastic system approximations; static aerodynamics for flutter analyses; flutter at high mach numbers; an indicial flutter analysis for hypersonic delta wings; a theory for aeroelastic studies of delta lifting surfaces; flutter of flat panels in a low supersonic flow; flutter of rectangular panels; model flight testing on high-speed tracks; liquid behavior in rocket propellant tanks; dynamics of LP vehicles; aero-inertial control system; dynamic loads of missile configurations; wind loads on a vertically rising vehicle; random gust and taxi response calculations for delta wing aircraft; blast-loading on airfoils; stall buffeting loads; a method for analyzing heated wings; deformational response of heated wing structures; thermal stiffness; acoustic fatigue tests for elevated temperatures structural design; structural vibration in space vehicles; structural response in noise inputs; captive missile response to random pressures; structural response to the noise input of the Saturn engines; the environmental vibration problem.

Lunar Lander Training Vehicle (LLTV) Drawing No. 757835