Browsing Fakultät für Physik (inkl. GAUSS) by Referee "Tilgner, Andreas Prof. Dr."
Now showing items 21-40 of 52
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Moist Rayleigh Benard Convection
(2018-10-19)Clouds play an important yet poorly understood role in weather forecasting and climate change. The objective in the present work is to establish a laboratory-scale experiment for simulating clouds in the Earth's atmosphere. ... -
Inertial modes, turbulence and magnetic effects in a differentially rotating spherical shell
(2017-11-09)The study of a fluid trapped inside a spherical shell is of fundamental interest in fluid mechanics, having given rise to numerous theoretical and experimental studies. This is also a geometric feature shared by geo- ... -
Experimentelle Erfassung und Charakterisierung der dreidimensionalen großskaligen Strömungsstrukturen und -temperaturen in Rayleigh-Bénard-Konvektion
(2017-10-26)In this work the flow structures in Rayleigh-Benard-Convection (RBC) are experimentally studied. For this purpose, two cuboidal convection samples are designed and installed. Using water as working fluid, these two experiments ... -
Multi-instrument study of the hourly pulsations in Saturn’s magnetosphere
(2017-10-20)The in-situ exploration of the magnetospheres of Jupiter and Saturn has revealed various pulsed phenomena, some of them being periodic. In Saturn's magnetosphere, several studies have reported pulsations with a periodicity ... -
Untersuchungen zum Lumineszenzverhalten des Aluminiumnitrids und der Aufbau einer Kurzzeit-Lumineszenz-Spektroskopie-Apparatur
(2017-07-07)This thesis consists of three different parts. In the first part it gives the reader an overview of the published results describing near band-edge as well as defect related luminescence in aluminium nitride, also presenting ... -
Microfluidic cells as a model 2D granular material
(2017-03-20)I have made quasi-2D granular analogs using microfabrication techniques common in microfluidics such as photo- and Soft Lithography. I have performed two kinds of experiments common in multiphase flow problems: drying and ... -
Magnetohydrodynamic Simulation of Reconnection in Turbulent Astrophysical Plasmas
(2016-08-31)Turbulence is ubiquitous at large-Reynolds-number astrophysical plasmas like in the Solar corona. In such environments, the turbulence is thought to enhance the energy conversion rate by magnetic reconnection above ... -
Crack patterns on uneven substrates
(2016-04-29)Cracks patterns are in uenced by the substrates beneath them. From buried craters to crocodile skin, crack patterns are found over an enormous range of length scales. Regardless of their scale, substrates can impart ... -
Experimentelle Untersuchungen von Fingerströmung und thermohalinen Treppen für instabile Auftriebsverhältnisse
(2016-04-19)Finger convection is observed experimentally in an electrodeposition cell in which a destabilizing gradient of copper ions is maintained against a stabilizing temperature gradient. This double-diffusive system shows finger ... -
Elliptical instability of compressible flow and dissipation in rocky planets for strong tidal forcing
(2016-02-02)This thesis is divided into three main parts, in accordance with Chapters 2, 3 and 4. In the first part, Chap. 2, we investigate the elliptical instability. We calculate the growth rates of the elliptical instability under ... -
Rotation and non-Oberbeck-Boussinesq effects in turbulent Rayleigh-Bénard convection
(2015-07-15)In this thesis different aspects of turbulent Rayleigh-Bénard convection have been studied that go beyond of what the majority of recent investigations focuses on. The two main concerns here, were the influence of rotation ... -
Experimental Acquisition and Characterisation of Large-Scale Flow Structures in Turbulent Mixed Convection
(2014-07-28)In this cumulative thesis, the superposition of shear flow and thermal convection, namely mixed convection, is investigated experimentally. The experiments were performed in a cuboidal sample with aspect ratios Gamma_xz = ... -
Boundary layers and wind in turbulent thermal convection
(2014-07-24)This cumulative thesis is based on seven publications and is devoted to the investigation of turbulent thermal convection by means of Direct Numerical Simulations (DNSs). Special focus is placed on the boundary layers and ... -
Subcritical Transition to Turbulence in Shear Flows
(2014-05-23)The theme of this thesis is transition to turbulence in linearly stable shear flows. Laminar-turbulent intermittency and hysteresis are typical feature of these flows at transitional Reynolds numbers, characterizing a ... -
Kinematic dynamo onset and magnetic field saturation in rotating spherical Couette and periodic box simulations
(2013-07-26)Magnetic fields are ubiquitous in the universe and can be found in celestial bodies, galaxies, stars including our Sun and planets like the Earth or Jupiter. Due to the fact that at least in the Earth's interior, temperatures ... -
Spatial Scaling of Large-Scale Circulations and Heat Transport in Turbulent Mixed Convection
(2013-02-18)The present study reports an experimental investigation of the scaling of large-scale coherent structures, their dynamics and heat transport in turbulent mixed convection. Based on a concept of spatial scaling, mixed ... -
Evolution of Droplet Distributions in Hydrodynamic Systems
(2012-01-04)For droplets in a supersaturated environment, a complex interplay of nucleation, diffusional growth, collisions and coalescences, sedimentation and dripping determines the evolution of their ... -
Numerical Simulations of the Gravitational Geodynamo and its Time Spectrum
(2011-06-30)This work contributes to the understanding of the dynamo mechanism. Gravitationally driven and convection driven dynamo simulations are studied. We analyzed dynamo mostly from the spectral ... -
Numerische Untersuchung rotierender Rayleigh-Bénard-Konvektion ohne Ekman-Schichten
(2010-02-05)This work deals with numerical studies of rotating Rayleigh-Bénard convection in a planar fluid layer. A spectral method is employed with periodic boundary conditions in the horizontal ... -
Pattern Formation in Spatially Forced Thermal Convection
(2010-02-04)In this work experimental results on forced thermal convection are presented. Experiments were done in a large aspect ratio cell slightly above the critical temperature difference at which ...