Search for dissertations about: "Area-expansion"

Found 4 swedish dissertations containing the word Area-expansion.

  2. 1. Methods and techniques for precise and accurate in-duct aero-acoustic measurements : Application to the area expansion

    Author : Luck Peerlings; Susann Boij; Hans Bodén; Yves Aurégan; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Area-expansion; Scattering matrix; Multi-microphone method; Engineering Mechanics; Teknisk mekanik;

    Abstract : During the design and commissioning of combustion equipment, combustion associated instabilities are commonly encountered. These thermo-acoustic instabilities can cause undesirable noise, vibrations, local thermal and mechanical stresses in the combustor and are prominent in lean combustion. READ MORE

  4. 2. Assessing precision and accuracy in acoustic scattering matrix measurements

    Author : Luck Peerlings; Hans Bodén; Susann Boij; Avraham Hirschberg; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aero-acoustics; sudden area expansion; in-duct acoustics; acoustic scattering matrix; impedance tube; uncertainty analysis; systematic errors; Vehicle and Maritime Engineering; Farkostteknik;

    Abstract : Acoustic scattering matrices are used to characterize the influence of inline duct elements on the acoustic wave propagation in wave guides.When measuring the properties of these matrices, errors are always present in the results and need to be characterized to make valid statements on the correspondence between model predictions and measurements. READ MORE

  5. 3. Statistical aspects of modeling panel data originating from smallholder household surveys in Sub-Saharan Africa and Vietnam

    Author : Sultana Nasrin; Statistiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; power of test; endogeneity; multivariate; longitudinal data; diversification;

    Abstract : This thesis focuses on multivariate multilevel modeling of panel data originated from smallholder farm surveys in Sub-Saharan African (SSA) countries and Vietnam to investigate driving forces in maize and rice production in SSA and diversification of farms in the rice sector in Vietnam. We also present and evaluate different tests for endogeneity in explanatory binary variables in multivariate linear regression models. READ MORE

  6. 4. Acoustic scattering in ducts and influence of flow coupling

    Author : Susann Boij; KTH; []
    Keywords : sound; vortex sheet; flow separation; end correction; Strouhal number; non-orthogonal modes; energy balance; TECHNOLOGY; TEKNIKVETENSKAP;

    Abstract : The subject of this thesis is the acoustic properties offlow duct area expansions and the influence of flow-acousticcoupling at sharp edges. For low Mach number flow, significantinteraction between the sound field and the flow field canoccur at such points of flow separation. READ MORE