The effect of wall cooling on a compressible turbulent boundary layer

Experimental results are presented for two turbulent boundary-layer experiments conducted at a free-stream Mach number of 4 with wall cooling. The first experiment examines a constant-temperature cold-wall boundary layer subjected to adverse and favourable pressure gradients. It is shown that the boundary-layer data display good agreement with Coles’ general composite boundary-layer profile using Van Driest's transformation. Further, the pressure-gradient parameter β_K found in previous studies to correlate adiabatic high-speed data with low-speed data also correlates the present cooled-wall high-speed data. The second experiment treats the response of a constant-pressure high-speed boundary layer to a near step change in wall temperature. It is found that the growth rate of the thermal boundary layer within the existing turbulent boundary layer varies considerably depending upon the direction of the wall temperature change. For the case of an initially cooled boundary layer flowing onto a wall near the recovery temperature, it is found that δ_T ~ x whereas the case of an adiabatic boundary layer flowing onto a cooled wall gives δ_T ~ x^½. The apparent origin of the thermal boundary layer also changes considerably, which is accounted for by the variation in sublayer thicknesses and growth rates within the sublayer

Fluorescence visualization of a convective instability which modulates the spreading of volatile surface films

The spontaneous spreading of a thin liquid film along the surface of a deep liquid layer of higher surface tension is a ubiquitous process which provides rapid and efficient surface transport of organic or biological material. For a source of constant concentration, the leading edge of a nonvolatile, immiscible film driven to spread by gradients in surface tension is known to advance as t^3/4 in time. Recent experiments using laser shadowgraphy to detect the advancing front of spreading films indicate, however, that immiscible but volatile sources of constant concentration spread with a reduced exponent according to t^1/2. Using a novel technique whereby fluorescent lines are inscribed in water, we have detected the evolution of a thermal instability beneath the leading edge of volatile films which strongly resembles a Rayleigh-Bénard roll. We propose that the increased dissipation from this rotational flow structure is likely responsible for the reduction in spreading exponent. This observation suggests a conceptual framework for coupling the effects of evaporation to the dynamics of spreading

The NASA SBIR product catalog

The purpose of this catalog is to assist small business firms in making the community aware of products emerging from their efforts in the Small Business Innovation Research (SBIR) program. It contains descriptions of some products that have advanced into Phase 3 and others that are identified as prospective products. Both lists of products in this catalog are based on information supplied by NASA SBIR contractors in responding to an invitation to be represented in this document. Generally, all products suggested by the small firms were included in order to meet the goals of information exchange for SBIR results. Of the 444 SBIR contractors NASA queried, 137 provided information on 219 products. The catalog presents the product information in the technology areas listed in the table of contents. Within each area, the products are listed in alphabetical order by product name and are given identifying numbers. Also included is an alphabetical listing of the companies that have products described. This listing cross-references the product list and provides information on the business activity of each firm. In addition, there are three indexes: one a list of firms by states, one that lists the products according to NASA Centers that managed the SBIR projects, and one that lists the products by the relevant Technical Topics utilized in NASA's annual program solicitation under which each SBIR project was selected

Langley aerospace test highlights, 1985

The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Significant tests which were performed during calendar year 1985 in Langley test facilities, are highlighted. Both the broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research, are illustrated. Other highlights of Langley research and technology for 1985 are described in Research and Technology-1985 Annual Report of the Langley Research Center

Assessment on the Efficiency of an Active Solar Thermal Facade: Study of the Effect of Dynamic Parameters and Experimental Analysis When Coupled/Uncoupled to a Heat Pump

The building sector presents poor performance in terms of energy efficiency and is looking for effective alternatives aimed at reducing the use of fossil fuels. The facade is a key element able to harness renewable energy as an Active Solar Thermal Facade (ASTF). The main purpose of this study is the assessment of a novel design concept based on a steel sandwich panel technology. The performance of the active system will be first addressed by a parametric study in order to analyze its behavior and secondly, by describing a real case based on an experimental test by connecting the active panels to a heat pump. The study shows the impact of solar irradiation and mass flow on the thermal jump achieved, while ambient and fluid inlet temperatures are the most influencing parameters in the efficiency of the facade. When coupled to the heat pump, results from a measurement campaign demonstrate a remarkable improvement in the performance of the ASTF. The results presented provide significant proof about the benefits of a synergetic combination of both technologies—solar facades and heat pumps—as efficient alternatives for the building sector, aiming to improve energy efficiency as well as reduce their dependence on non-renewable sources.This research was partially funded by the Basque Government through IT781-13 and IT1314-19 research groups and by the University of the Basque Country UPV/EHU through PES17/25. Additionally, TECNALIA Research & Innovation supported the research activities research through a cooperation agreement (PT10516) with UPV/EHU

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 212

A bibliography listing 146 reports, articles, and other documents introduced into the NASA scientific and technical information system is presented. The subject coverage concentrates on the biological, psychological, and environmental factors involved in atmospheric and interplanetary flight. Related topics such as sanitary problems, pharmacology, toxicology, safety and survival, life support systems, and exobiology are also given attention

Review of experimental research on supercritical and transcritical thermodynamic cycles designed for heat recovery application

Supercritical operation is considered a main technique to achieve higher cycle efficiency in various thermodynamic systems. The present paper is a review of experimental investigations on supercritical operation considering both heat-to-upgraded heat and heat-to-power systems. Experimental works are reported and subsequently analyzed. Main findings can be summarized as: steam Rankine cycles does not show much studies in the literature, transcritical organic Rankine cycles are intensely investigated and few plants are already online, carbon dioxide is considered as a promising fluid for closed Brayton and Rankine cycles but its unique properties call for a new thinking in designing cycle components. Transcritical heat pumps are extensively used in domestic and industrial applications, but supercritical heat pumps with a working fluid other than CO2 are scarce. To increase the adoption rate of supercritical thermodynamic systems further research is needed on the heat transfer behavior and the optimal design of compressors and expanders with special attention to the mechanical integrity

RV Sonne Cruise 200, 11 Jan-11 Mar 2009. Jakarta - Jakarta

All plate boundaries are divided into segments - pieces of fault that are distinct from oneanother, either separated by gaps or with different orientations. The maximum size of anearthquake on a fault system is controlled by the degree to which the propagating rupture cancross the boundaries between such segments. A large earthquake may rupture a whole segmentof plate boundary, but a great earthquake usually ruptures more than one segment at once.The December 26th 2004 MW 9.3 earthquake and the March 28th 2005 MW 8.7 earthquakeruptured, respectively, 1200–1300 km and 300–400 km of the subduction boundary betweenthe Indian-Australian plate and the Burman and Sumatra blocks. Rupture in the 2004 eventstarted at the southern end of the fault segment, and propagated northwards. The observationthat the slip did not propagate significantly southwards in December 2004, even though themagnitude of slip was high at the southern end of the rupture strongly suggests a barrier at thatplace. Maximum slip in the March 2005 earthquake occurred within ~100 km of the barrierbetween the 2004 and 2005 ruptures, confirming both the physical importance of the barrier,and the loading of the March 2005 rupture zone by the December 2004 earthquake.The Sumatran Segmentation Project, funded by the Natural Environment Research Council(NERC), aims to characterise the boundaries between these great earthquakes (in terms of bothsubduction zone structure at scales of 101-104 m and rock physical properties), record seismicactivity, improve and link earthquake slip distribution to the structure of the subduction zoneand to determine the sedimentological record of great earthquakes (both recent and historic)along this part of the margin. The Project is focussed on the areas around two earthquakesegment boundaries: Segment Boundary 1 (SB1) between the 2004 and 2005 ruptures atSimeulue Island, and SB2 between the 2005 and smaller 1935 ruptures between Nias and theBatu Islands.Cruise SO200 is the third of three cruises which will provide a combined geophysical andgeological dataset in the source regions of the 2004 and 2005 subduction zone earthquakes.SO200 was divided into two Legs. Leg 1 (SO200-1), Jakarta to Jakarta between January 22ndand February 22nd, was composed of three main operations: longterm deployment OBSretrieval, TOBI sidescan sonar survey and coring. Leg 2 (SO200-2), Jakarta to Jakarta betweenFebruary 23rd and March 11th, was composed of two main operations: Multichannel seismicreflection (MCS) profiles and heatflow probe transects

Small business innovation research. Abstracts of completed 1987 phase 1 projects

Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Thermographic Particle Velocimetry (TPV) for Simultaneous Interfacial Temperature and Velocity Measurements

AbstractWe present an experimental technique, that we refer to as ‘thermographic particle velocimetry’ (TPV), which is capable of the simultaneous measurement of two-dimensional (2-D) surface temperature and velocity at the interface of multiphase flows. The development of the technique has been motivated by the need to study gravity-driven liquid-film flows over inclined heated substrates, however, the same measurement principle can be applied for the recovery of 2-D temperature- and velocity-field information at the interface of any flow with a sufficient density gradient between two fluid phases. The proposed technique relies on a single infrared (IR) imager and is based on the employment of highly reflective (here, silver-coated) particles which, when suspended near or at the interface, can be distinguished from the surrounding fluid domain due to their different emissivity. Image processing steps used to recover the temperature and velocity distributions include the decomposition of each original raw IR image into separate thermal and particle images, the application of perspective distortion corrections and spatial calibration, and finally the implementation of standard particle velocimetry algorithms. This procedure is demonstrated by application of the technique to a heated and stirred flow in an open container. In addition, two validation experiments are presented, one dedicated to the measurement of interfacial temperature and one to the measurement of interfacial velocity. The deviations between the results generated from TPV and those from accompanying conventional techniques do not exceed the errors associated with the latter