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Professor Wojciech Majewski - His 70th Jubilee

100%

Wilde P.

tom Vol. 49, nr 3

7-10

Vibrations of a plate in fluid and associated damping due to energy transmission by dilatational waves

84%

Wilde P. , Szmidt J. K.

Journal of Theoretical and Applied Mechanics

1999

tom nr 2

267-282

The paper presents a solution to the problem of harmonic vibrations of a plate submerged in an unbounded medium of inviscid compressible fluid. The solution is obtained, as a limiting case, by means of a solution to the problem of an infinite elliptic cylinder vibrating in the fluid. The latter problem is solved with the help of the Fourier method of separation of variables in the elliptic coordinate system. For comparison purposes, a similar problem of circular cylinder vibrating in the fluid is also investigated. From the discussion presented it follows, that the fluid compressibility is essential in estimating hydrodynamical forces, especially in calculating damping of plate vibrations for higher frequencies.

W pracy przedstawiono rozwiązanie zagadnienia drgań harmonicznych płyty zanurzonej w nieograniczonym obszarze ściśliwej cieczy nielepkiej. Rozwiązanie to otrzymano za pomocą przejścia granicznego w zbudowanym rozwiązaniu dla nieskończonego walca eliptycznego drgającego w cieczy. Ten ostatni problem rozwiązano za pomocą metody Fouriera rozdzielenia zmiennych w eliptycznym układzie współrzędnych. Dla porównania, wyznaczono również rozwiązanie dla drgań walca kołowego zanurzonego w cieczy. Z przedstawionej dyskusji wynika, że ściśliwość cieczy jest podstawowym parametrem w opisie sił hydrodynamicznych, a szczególnie -- --tłumienia drgań płyty dla wyższych częstości.

On variational formulation in water wave mechanics

84%

Wilde P. , Szmidt J. K.

Archives of Hydro-Engineering and Environmental Mechanics

2004

tom Vol. 51, nr 1

55-74

In this paper variational formulations for surface gravitational waves in inviscid incompressible fluids are investigated. The formulations are introduced with the help of the principle of virtual work. The starting point are equations of motion multiplied by a field of virtual displacements and integrated over the region occupied by the fluid. In derivations of the virtual work equation careful attention is paid to mutual relations between Eulerian and Lagrangian descriptions. The integration of the equation with respect to time leads to the expression for the Lagrangian function and then the Hamilton's principle. The case of a potential flow and spatial description provides a generalisation of the Lagrangian given by Luke (1967).

Long water waves as a structure fluid interaction problem

84%

Wilde P. , Chybicki W.

Archives of Hydro-Engineering and Environmental Mechanics

2004

tom Vol. 51, nr 2

95-118

The paper describes a new formulation of the theory of long shallow water waves, which is based on the fundamental assumption that vertical material lines of fluid remain vertical during the entire motion. To make the problem consistent from the point of view of physics the case of waves in a flume due to the motion of a piston type generator is considered. At the piston the material line of water particles remains vertical during the entire motion and thus the generation follows the assumption in the description of the motion of water in the flume. Wave equations are derived with the help of a variational formulation of the problem in a material description. The Lagrangian is the difference between the kinetic and potential energies of the fluid and the mechanical system that describes a very simplified wave generator. The basic assumption simplifies the geometry of the displacement field. The definitions of generalized forces follow from variational calculus. The procedure ensures that the energy is preserved. A simple discrete formulation of the problem is based on the finite element method and the corresponding approximate expressions for energies.

Rozwój badań w zakresie dynamiki budowli morskich w Instytucie Budownictwa Wodnego PAN w Gdańsku

84%

Wilde P. , Szmidt J. K.

Inżynieria Morska i Geotechnika

2001

tom nr 6

386-388

Estimation of general and specific combining ability variances and their implications on hybrid rye breeding

67%

Wilde P. , Menzel J. , Schmiedchen B.

nr 1

Combining ability vs. population performance of genetic resources in rye

51%

Roux S. R. , Miedaner T. , Geiger H. H. , Knopf E. , Wilde P. , Wortmann H.

nr 2