1984 Cilt 1 Sayı 1

Permanent URI for this collectionhttps://hdl.handle.net/11452/31800

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    Effecfs of gravity on interdendritic fluid flow in large remelted ingots
    (Uludağ Üniversitesi, 1984) Yerebakan, Metin; Mühendislik Fakültesi; Makine Mühendiliği Bölümü
    This paper presents analytic calculations of the interdendritic fluid-flow in mush zones whose width is small compared to their length, a situation which is caracteristic of large remelted ingots. The flow is found to consist of two main components. The first one is normal to the isotherms which feeds solidifi­cation shrinkage and the second one is parallel to the isotherms which is produced by gravity acting on desity differences in the interdendritic liquid. If the isotherms are not exactly parallel, then the gravity induced flow parallel to the isotherms induces a component normal to it. This companent may cause the freckles that occur in remelted ingots when melting conditions are changed.
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    Elastic and geometric stiffness matrices for thın walled stiffener element
    (Uludağ Üniversitesi, 1984) Saylan, Şerif; Toridis, Theodore
    Elastic and geometric stiffness matrices for a structural stiffener member are obtained using the differential equations given by Chen and Atsuta 4. Presence of additional elements over the conventional form is observed in the geometric Stiffness matrix. The known transformation matrix is used to express the elements displacements with respect to the middle surface of the stiffened plate.
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    Otomotiv endüstrisindeki gelişmeler
    (Uludağ Üniversitesi, 1984) Borat, Oğuz; Mühendislik Fakültesi; Makina Bölümü
    The problems of the automotive industries, arised by the various constraints such as air pollution, decrease of fossil fuels, usage of alternative fuels, noise pollution, safety, fuel economy, etc., are studied under the titles of alternative fuels, alternative engines and technical improvements. Resultingly, the research subjects and the technological trends, required for solutions reductions of the problems to be faced in the short and long terms, are discussed.
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    Prediction of some turbulent flows using upwind and hybrid discretısa tion schemes and the two-eouation turbulence model
    (Uludağ Üniversitesi, 1984) Choudhury, P. Roy; Gerstein, M.; Karasu, Tahir; Mühendislik Fakültesi; Makine Mühendisliği Bölümü
    The paper presents the use of a numerical solution procedure for the prediction of steady, in­ compressible and two-dimensional turbulent flow in a pipe, in sudden expansions in pipes, and over a back­ ward-facing step using upwind and hybrid discretisation schemes. The numerical procedure employs a two-equation turbulence model, which entails the solution of two differential equations of transport for characteristics of turbulence; nameIy, the kinetic energy of tur­bulence and its rate of dissipation. The Reynolds stresses are related to the mean velocity gradients through a scalar turbulent viscosity, calculated from the above turbulence variables. In the near-wall regions, wall functions are employed. The predictions results from simultaneous solution of differential equations for conservation of mass and momentum, together with equations describing the transport of turbulence, by means of a finite-difference solution procedure. The predictions obtained using upwind and hybrid discretisation schemes are compared with each other and with published experimental data. For flows in which recirculation is present, the use of hybrid scheme results in closer agreement with measurements. In general, the predictions made are in good qualitative agreement with experiment.