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[en] In this summary first the importance and recent successes of fluid dynamics will be discussed. Then achievements in vital ingredients of a fluid dynamical model, the initial conditions and the final freeze out will be presented. In the discussion of the fluid dynamical model the talks discussing viscosity, dissipation and related problems will be reviewed. In conclusion some remarks will be presented on the future outlook of this approach
[en] A matter of great interest to variable star students concerns the mode of pulsation of Mira long period variables. In this report we first give observational evidence for the pulsation constant Q. We then compare the observations with calculations. Next, we review two interesting groups of papers dealing with hydrodynamic properties of long period variables. In the first, a fully dynamic nonlinear calculation maps out the Mira instability domain. In the second, special attention is paid to shock propagation beyond the photosphere which in large measure accounts for the complex spectra from this region. (orig./WL)
[en] We present in these notes two methods to derive the hydrodynamic equation of conservative interacting particle systems. The intention is to present the main ideas in the simplest possible context and refer for details and references. (author)
[en] A modeling study was conducted to evaluate additional project design scenarios at the Union Slough restoration/mitigation site during low tide and to provide recommendations for finish-grade elevations to achieve desired drainage. This was accomplished using the Snohomish River hydrodynamic model developed previously by PNNL.
[en] In this work we construct and analyze continuous hydrodynamic models in one space dimension, which are induced by shell models of turbulence. After Fourier transformation, such continuous models split into an infinite number of uncoupled subsystems, which are all identical to the same shell model. The two shell models, which allow such a construction, are considered: the dyadic (Desnyansky–Novikov) model with the intershell ratio λ = 23/2 and the Sabra model of turbulence with . The continuous models allow for understanding of various properties of shell model solutions and provide their interpretation in physical space. We show that the asymptotic solutions of the dyadic model with Kolmogorov scaling correspond to the shocks (discontinuities) for the induced continuous solutions in physical space, and the finite-time blowup together with its viscous regularization follow the scenario similar to the Burgers equation. For the Sabra model, we provide the physical space representation for blowup solutions and intermittent turbulent dynamics. (paper)
[en] The three-dimensional flow of an initially flat and hot disc is discussed, by fixing the attention especially to the energy dependence of the transverse expansion. As the total energy M increases, dN/dξ increases at the same time so that its maximum moves outward giving an increasing <ξ> which is close to the value estimated by Milekhin. This may be the natural explanation for the observed Δn/Δy - < rho/sub perpendicular/> correlation
[en] Butterfly valves have been widely used for on-off or control purposes in the process industry, since they provide quick opening and closing operation and good flow control characteristics. For the evaluation of the adequacy of valve operability and the actuator sizing, the required torque estimation is necessary. Since the principal contributing component of the require torque in the mid-stroke position is hydrodynamic torque, it is necessary to predict the torque properly under the actual flow conditions. The research on the prediction of the valve performance was led by EPRI (Electric Power Research Institute) in early 1990s. A performance prediction model was developed based on the experimental results and the free-streamline analysis by Sarpkaya. Recently, Kalsi Engineering carried out extended tests and developed the improved model. Variation of disk geometries and upstream flow conditions were tried to obtain accurate hydrodynamic torque coefficients. However, since the model is only commercially available, a general method to obtain hydrodynamic torque for butterfly valves is called for
[en] Complete text of publication follows. We present a model to describe the interplanetary coronal mass ejections (ICMEs) dynamics in their travel from Sun to Earth. The model is based on the assumption of momentum transfer between ICMEs and the surrounding solar wind that decelerate the fast ICMEs (Vcme > Vsw). In this case, the deceleration involves viscous forces acting between the ICME and the surrounding medium. In our model we include the variability of the mass density of the medium as well as the variability of the CME radius. The obtained result is the speed behavior of the ICMEs versus traveled distance. The solution of the differential equations is found considering different expressions for the viscous force. In this work we present the analytical solutions and compare them with observed parameters for a selected group of events. The observed parameters we consider in our analyses are: initial speed of CMEs, final speed of ICMEs, travel time from Sun to the observation point, and solar wind speed. We also consider the ICME mass, the variation of the interplanetary density, the exponent of radial expansion of the ICME, and the drag coefficient (or the kinematic viscous coefficient). The best values for the latest parameters are obtained trough an iterative procedure, where only one parameter is varied until a valid solution is found. We also show that our model qualitative agrees with observations of Type II bursts as well as with existing empirical models.