Use of surface heat transfer measurements as a flow separation diagnostic in a two dimensional reflected oblique shock/turbulent boundary layer interaction

The feasibility of using streamwise surface heat transfer measurements to detect the presence of flow separation in a two-dimensional reflected oblique shock/turbulent boundary layer interaction is reported. Surface heat transfer and static pressure data are presented for attached and separated flows for a free stream nominal Mach number range of 2.5 to 3.5 and shock generator angles of 2 to 8 degrees. The static pressure data do show the characteristic triple inflection point distribution for the strongly separated flow cases. The corresponding surface heat transfer data show unique trends that correlate well with the static pressure determination of the extent of the separated flow region. For the incipient or weakly separated flow cases, the static pressure data do not exhibit the characteristic triple inflection point distribution. However, the same trends in the heat transfer data that are seen for the strongly separated flow cases are evident for the weakly separated flows. Hence, the heat transfer data can be used to determine the extent of weakly separated flows when the surface static pressure distributions often can not

Heat transfer, velocity-temperature correlation, and turbulent shear stress from Navier-Stokes computations of shock wave/turbulent boundary layer interaction flows

The properties of 2-D shock wave/turbulent boundary layer interaction flows were calculated by using a compressible turbulent Navier-Stokes numerical computational code. Interaction flows caused by oblique shock wave impingement on the turbulent boundary layer flow were considered. The oblique shock waves were induced with shock generators at angles of attack less than 10 degs in supersonic flows. The surface temperatures were kept at near-adiabatic (ratio of wall static temperature to free stream total temperature) and cold wall (ratio of wall static temperature to free stream total temperature) conditions. The computational results were studied for the surface heat transfer, velocity temperature correlation, and turbulent shear stress in the interaction flow fields. Comparisons of the computational results with existing measurements indicated that (1) the surface heat transfer rates and surface pressures could be correlated with Holden's relationship, (2) the mean flow streamwise velocity components and static temperatures could be correlated with Crocco's relationship if flow separation did not occur, and (3) the Baldwin-Lomax turbulence model should be modified for turbulent shear stress computations in the interaction flows

A laser-induced heat flux technique for convective heat transfer measurements in high speed flows

A technique is developed to measure the local convective heat transfer coefficient on a model surface in a supersonic flow field. The technique uses a laser to apply a discrete local heat flux at the model test surface, and an infrared camera system determines the local temperature distribution due to the heating. From this temperature distribution and an analysis of the heating process, a local convective heat transfer coefficient is determined. The technique was used to measure the local surface convective heat transfer coefficient distribution on a flat plate at nominal Mach numbers of 2.5, 3.0, 3.5, and 4.0. The flat plate boundary layer initially was laminar and became transitional in the measurement region. The experimentally determined convective heat transfer coefficients were generally higher than the theoretical predictions for flat plate laminar boundary layers. However, the results indicate that this nonintrusive optical measurement technique has the potential to measure surface convective heat transfer coefficients in high speed flow fields

The NASA Lewis Research Center Internal Fluid Mechanics Facility

An experimental facility specifically designed to investigate internal fluid duct flows is described. It is built in a modular fashion so that a variety of internal flow test hardware can be installed in the facility with minimal facility reconfiguration. The facility and test hardware interfaces are discussed along with design constraints of future test hardware. The plenum flow conditioning approach is also detailed. Available instrumentation and data acquisition capabilities are discussed. The incoming flow quality was documented over the current facility operating range. The incoming flow produces well behaved turbulent boundary layers with a uniform core. For the calibration duct used, the boundary layers approached 10 percent of the duct radius. Freestream turbulence levels at the various operating conditions varied from 0.64 to 0.69 percent of the average freestream velocity

Evaluation of a technique to generate artificially thickened boundary layers in supersonic and hypersonic flows

The feasibility of using a contoured honeycomb model to generate a thick boundary layer in high-speed, compressible flow was investigated. The contour of the honeycomb was tailored to selectively remove momentum in a minimum of streamwise distance to create an artificially thickened turbulent boundary layer. Three wind tunnel experiments were conducted to verify the concept. Results indicate that this technique is a viable concept, especially for high-speed inlet testing applications. In addition, the compactness of the honeycomb boundary layer simulator allows relatively easy integration into existing wind tunnel model hardware

Uso de sabiá (Mimosa caesalpiniifolia Benth) para valorização de sistemas agroextrativistas em babaçuais no Maranhão.

Este artigo apresenta a iniciativa de uma família agroextrativista em área de assentamento no município de São Luís Gonzaga do Maranhão, na busca de sistemas e práticas de manejo para produção de madeira associada ao extrativismo do babaçu, valorizando os babaçuais, fortalecendo a renda monetária e ampliando o leque de produtos para uso no estabelecimento. A experiência aponta para alternativas de cultivo que dispensam queimadas, contribuindo para a intensificação sustentável de sistemas tradicionais, proporcionando a conservação e utilização racional dos recursos naturais. Numa área de 1 ha, representativa da situação geral das terras do município, contendo 132 palmeiras de babaçu, foram plantadas 4.000 mudas de sabiá em fileiras com espaçamento de 5 metros. O experimento avalia o número e diâmetro das hastes de sabiá, e a altura do fuste. As observações até o momento apontam para resultados econômicos, ambientais e sociais promissores: viabiliza-se a recuperação de áreas degradadas, gera-se renda monetária liquida superior a R$18.000 em ciclo de cinco anos, por meio da produção de madeira (estacas para cercas) e babaçu, potencializam-se oportunidades para integração de atividades como a criação de abelhas melíferas e a introdução de espécies frutíferas intercalares, assim como constata-se o aumento na produção de babaçu, comparado a capoeiras utilizadas no sistema tradicional

Development of a laser-induced heat flux technique for measurement of convective heat transfer coefficients in a supersonic flowfield

A technique is developed to measure the local convective heat transfer coefficient on a model surface in a supersonic flow field. The technique uses a laser to apply a discrete local heat flux at the model test surface, and an infrared camera system determines the local temperature distribution due to heating. From this temperature distribution and an analysis of the heating process, a local convective heat transfer coefficient is determined. The technique was used to measure the load surface convective heat transfer coefficient distribution on a flat plate at nominal Mach numbers of 2.5, 3.0, 3.5, and 4.0. The flat plate boundary layer initially was laminar and became transitional in the measurement region. The experimental results agreed reasonably well with theoretical predictions of convective heat transfer of flat plate laminar boundary layers. The results indicate that this non-intrusive optical measurement technique has the potential to obtain high quality surface convective heat transfer measurements in high speed flowfields

The Clash between Global Master-plans and Local Contexts: conflicts and contradictions within initiatives for payment of ecosystem services in Brazil and Nepal.

With the development of large-scale international agreements, such as REDD (United Nations Collaborative Programme on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries), it is becoming increasingly important to examine the synergy between global masterplans, national endeavors and local actions in relation to environmental services provision and to mitigation and adaption to climate change. This paper will draw on a comparative study of two countries?, Brazil and Nepal, strategies and practices to deal with carbon emissions, i.e. examining the tensions and contradictions between mitigation agendas and the roles, practices and interests of the actors in the programmes and projects related to REDD. The data has been collected from contrasting case studies within the two countries (REDD and nonREDD cases). Preliminary evidence suggests that while the lack of synergy between global plans and local practices might be seen as simply a matter of ?coordination?, it actually reflects competing interests and agendas, both at national and local levels. The REDD plans are guided by a generic template, but how these plans are interpreted and implemented at national and local levels varies greatly, both between and within participating countries. The complexity of the REDD schemes creates a demand for actors who can plan and broker the processes. This complexity and the lack of an overarching reflexivity create a number of problems linked to transparency, complexity, lack of accountability and room for exploitation by powerful economic and political actors. This paper argues that these aspects often transform the planned results into unintended outcomes, depending on the particular configuration of local contextual factors and processes

A 'mãe palmeira' ante a privatização de terras sob uso comum: desafios para a conservação do babaçu por quilombolas no vale do Mearim, Brasil.

A relação entre palmeiras e comunidades é fator significativo para a constituição de territórios tradicionais e para a conservação de relevantes ecossistemas. Designada como 'mãe do povo', a palmeira babaçu 'Attalea speciosa (Mart. ex Spreng.)' tem provido historicamente o sustento de quilombos em terras de uso comum, nas áreas de sua ocorrência. Porém, contínuos assédios governamentais e civis de privatização ameaçam tais processos socioeconômicos e ecológicos, sob um mercado de terras desfavorável à tradição quilombola. É analisado o caso do quilombo Monte Alegre-Olho D'Água dos Grilos, no vale do rio Mearim, Maranhão, atualmente sob processo ilegal de privatização de terras coletivas. Quilombolas, em parceria de pesquisa-ação com os autores, realizaram inventário da vegetação arbórea no seu território. Resultados desse inventário e dados da memória oral sobre a vegetação arbórea permitem refletir sobre bases conceituais para a conservação dos babaçuais. Os resultados indicam que a regularização fundiária na modalidade coletiva é necessária, mas não suficiente para evitar a fragmentação da cobertura vegetal prejudicial à conservação florestal. Conclui-se que os direitos territoriais reivindicados, embora garantidos constitucionalmente, só serão concretizados se Estado e sociedade respeitarem a renovação da tradição do uso comum pelos quilombolas, conforme preconizado na revisada 'teoria dos comuns manejados

Seeking One's fortune elsewhere: the social breakdown of a smallholder settlement in the brazilian Eastern Amazon and the consequences for its rainforest reserve.

Using two cases, Anapu and São Manoel, located in the Brazilian Amazonian, this paper discusses the relationships between smallholders' capacity for collective action, smallholders' potential to unite and defend their territories, and the role of the state. In November 2017 a forest reserve of the settlement in Anapu was invaded by near 200 armed illegal squatters. We show how this event resulted from a gradual increase in internal tensions and loss of trust, thereby undermining attempts for collective action. A large reason for the lack of a functioning social network, reciprocal interactions and social trust is the migratory background of the settlers, which hinder the creation of extended kin networks, intermarriages between kin groups, as well as other forms of long-term networks of cooperation. This becomes clear when comparing Anapu to the social organization of the settlement of São Manoel in central Maranhão, which has been strong and functional for several decades. The reasons for the latter?s social coherence and trust is that it formed around interlinked extended kin groups. Collective resistance against a predatory large landowner in the 1980s contributed to forging trust and cohesion that could effectively be used to acquire and maintain collectively owned fields and cattle, to formalize an association and a cooperative and to negotiate social tensions within the community. The reciprocal network of São Manoel has made it possible for its settlers to use its more restricted natural resources to a sustainable extent, without negatively affecting the eco-system of their habitat