National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
Deformation and thermal evolution of the ice shell on Enceladus
Kvorka, Jakub ; Čadek, Ondřej (advisor) ; Souček, Ondřej (referee)
In the last two decades, successful space missions to Jupiter and Saturn provi- ded important data bearing information about topography and internal structure of icy bodies in the outer Solar System. Some of these bodies contain subsurface reservoirs of liquid water in contact with an outer shell made of solid ice. One of the possibilities how to explain the observed topography of a moon is to use its thermal production as the energy source that produces deformation of the ice crust covering the body. In this study, we develop a simplified mathematical mo- del of thermal-mechanical evolution of the ice crust including the effect of phase transition at its bottom boundary. The appropriate system of partial differential equations is coded in Fortran95 and used to study the surface features developed in response to heat flux anomalies imposed on the top of the subsurface ocean. The results obtained for Enceladus, Europa and Titan show that the observed topography of these moons can be explained only for a large grain size and the ice crust behaving elastically near the upper boundary. 1
Numerické modelování proudění vody v nitru ledových těles
Krivoš, Martin ; Čadek, Ondřej (advisor) ; Hanyk, Ladislav (referee)
Title: Numerical modeling of liquid water flows in ice bodies' interiors Author: Martin Krivoš Department: Department of Geophysics Supervisor: prof. RNDr. Ondřej Čadek, CSc., Department of Geophysics Abstract: We studied the flow induced by water jets in the subsurface oceans on the Solar system moons - Europa and Enceladus. In water plumes of Enceladus Cassini spacecraft detected small silica particles with radii ≈ 6 − 9 nm. As shown by experiments, these particles grow in size with time spent in the ocean. The small size of particles suggests that the material transport from the the jets on the oceanic floor to the source of the plume at the moon's surface is highly efficient. In the thesis we investigate the characteristic transport time by solving the Navier-Stokes equation for incompressible fluid. For this purpose we have developed a Fortran program in two-dimensional Cartesian geometry based on the finite-difference staggered-grid method. Another program, using the second order Runge-Kutta method, was written to reconstruct the trajectories of the particles in the ocean. Using these tools we estimated the effectiveness of material transport under different conditions, namely presence of global lateral flow, width of the water jet, the Reynolds number and the number of jets. Keywords: Navier-Stokes equation,...

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