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Analysis of classical and spectral finite element spatial discretization in one-dimensional elastic wave propagation
Kolman, Radek ; Plešek, Jiří ; Okrouhlík, Miloslav ; Gabriel, Dušan
The spatial discretization of continuum by finite element method introduces the dispersion error to numerical solutions of stress wave propagation. For higher order finite elements there are the optical modes in the spectrum resulting in spurious oscillations of stress and velocity distributions near the sharp wavefront. Spectral finite elements are of h-type finite element, where nodes have special positions along the elements corresponding to the numerical quadrature schemes, but the displacements along element are approximated by Lagrangian interpolation polynomials. In this paper, the classical and Legendre and Chebyshev spectral finite elements are tested in the one-dimensional wave propagation in an elastic bar.
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Modelling of toxic gases substituents on the model of the Old Town Square in Prague
Bezpalcová, Klára
The model of the place and its vicinity was manufactured, an atmospheric boundary layer in the appropriate scale (i.e. in scale 1:270, in which the model was manufactured) was created in the wind tunnel, and the climatology of the location was study in order to select prevailing wind directions in the frame of the experiment preparation. Also a flow visualization using a smoke generator and laser sheet was conducted. The concentration of the toxic gas substituents (propan and pentyl acetate) were measured in the location of the Old Town Square in Pargue for 4 different source locations (corner of the Pařížské street, Hus monument, City Hall tower a passage by U Prince) and for 5 prevailing wind directions (NW, WNW, W, WSW, SW).
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The effect of input pulse shape on stress wave propagation in a thick plate
Hora, Petr
The effect geometrical dispersion is that the energy in a wave-packet propagates at different speeds depending on its frequency. It is shown that duration of a wave-packet increases linearly with propagation distance and also that the duration of a wave-packet after a given propagation distance depends on the input signal. Some conclusions are made concerning the Lamb wave propagation in a steel plate.
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The effect of geometrical dispersion on stress wave propagation
Hora, Petr
The effect geometrical dispersion is that the energy in a wave-packet propagates at different speeds depending on its frequency. It is shown that duration of a wave-packet increases linearly with propagation distance and also that the duration of a wave-packet after a given propagation distance depends on the input signal. Some conclusions are made concerning the Lamb wave propagation in a steel plate.
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