Дисертації з теми "Stratified boundary layer"
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Taylor, John R. "Numerical simulations of the stratified oceanic bottom boundary layer." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3296822.
Повний текст джерелаTitle from first page of PDF file (viewed March 24, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 205-212).
Baum, Bryan Alan. "The extension of rapid distortion theory to stratified shear flows." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/25971.
Повний текст джерелаRees, J. M. "Studies of internal gravity waves in the stably stratified troposphere." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383343.
Повний текст джерелаZhou, Jingnan. "Numerical studies of stably stratified planetary boundary-layer flows over topography and their parameterization for large scale numerical model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq27395.pdf.
Повний текст джерелаApsley, David D. "Numerical modelling of neutral and stably stratified flow and dispersion in complex terrain." Thesis, University of Surrey, 1995. http://epubs.surrey.ac.uk/649/.
Повний текст джерелаJiménez, Cortés Maria Antònia. "Stably stratified atmospheric boundary layer: study trough large-eddy simulations, mesoscale modelling and observations." Doctoral thesis, Universitat de les Illes Balears, 2005. http://hdl.handle.net/10803/9433.
Повний текст джерелаAquest treball es centra en l'estudi de la CLE mitjançant 3 eines diferents: 1) simulacions explícites de grans remolins (més conegudes com a simulacions LES), per determinar el comportament dels moviments turbulents, on les resolucions són de l'ordre de metres; 2) simulacions mesoscalars, per caracteritzar els efectes locals, on les resolucions són de l'ordre de kilòmetres; 3) anàlisi de les observacions sota aquestes condicions per tal de caracteritzar i entendre millor els fenòmens observats.
En primer lloc s'estudia el rang d'estabilitats a on el model LES, que considera la teoria de Kolmogorov per la dissipació de l'energia, funciona correctament. Els resultats del model són realistes tal com mostra la seva comparació amb les mesures de dues campanyes experimentals (SABLES-98 i CASES-99). Per explorar més a fons els resultats LES i per comparar-los amb les mesures s'han utilitzat les Funcions de Distribució de Probabilitat (PDF). Aquests resultats LES són també comparables als obtinguts amb altres models LES, tal com mostra la intercomparació de models LES, més coneguda com a GABLS.
Un cop desenvolupades totes les eines necessàries es fa un LES d'un cas més realista, basat en les observacions d'un màxim de vent de capes baixes (més conegut com a Low-Level Jet, LLJ). L'anàlisi combinat dels resultats LES i les mesures permet entendre millor els processos de barreja que tenen lloc a través de la inversió. Finalment, la contribució dels efectes locals s'estudia mitjançant les simulacions mesoscalars, en aquest cas centrades a l'illa de Mallorca. Durant el vespre es veu com les circulacions locals es desenvolupen a les conques (de longitud al voltant de 25km), formant-se, per exemple, vents catabàtics o LLJ com l'estudiat anteriorment. En aquest cas les simulacions es verifiquen amb imatges de satèl·lit NOAA i observacions de les estacions automàtiques de mesures, donant resultats semblants.
The atmospheric boundary layer is the area directly influenced by the presence of the Earth's surface and its height is from hundreds of meters to few kilometres. During the night, the radiative cooling stratifies the layer close to the surface and it forms the Stably-stratified Atmospheric Boundary Layer (SBL). Nowadays, the SBL is a regime not well enough characterized, yet. Turbulence, which is not homogeneous either isotropic, and the great importance of the local effects, like the orography, among other factors, make the SBL be a difficult regime to study. Even so, the SBL is an object of special attention, especially when improving its representation in numerical prediction models or climate models.
This work focuses on the study of the SBL through 3 different tools: 1) Large-Eddy Simulations (LES), to determine the turbulent motions, where the resolutions are about 1m; 2) Mesoscale simulations, to characterize the local effects, where resolutions are about 1km; 3) Analysis of the observations under these conditions in order to better characterize and understand the observed phenomena.
In first place, it is studied the range of stabilities where the LES model, that considers the Kolmogorov theory for the dissipation of the energy, works correctly. The results are realistic as the comparison with measures from two experimental campaigns (SABLES-98 and CASES-99) shows. To explore the results more thoroughly, and to compare the LES results to the measurements, the Probability Density Functions (PDF) have been used. The LES results are also comparable to the ones obtained with other LES models, as the intercomparison of different LES models show, better known as GABLS.
Then, a more realistic case is performed using the LES model, based on observations of a Low-Level Jet (LLJ). The combined inspection of the LES results and the observations allow to better understand the mixing processes that take place through the inversion layer. Finally, the contribution of the local effects is studied through a mesoscale simulation. Here the attention is focused on the Mallorca Island. During the night, the model is able to reproduce the local circulations is a basin of a characteristic size of 25km. The main features obtained previously from the LES of the LLJ are also reproduced by the mesoscale model. These runs are verified with NOAA satellite images and observations from the automatic surface weather stations, giving that the model is able to reproduce realistic results.
FRANCONE, CATERINA. "Study of the atmospheric boundary layer processes over sloping terrain covered by sparse canopy." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2496734.
Повний текст джерелаUdina, Sistach Mireia. "Modeling the atmospheric boundary layer in stably stratified conditions and over complex terrain areas: from mesoscale to LES." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/396115.
Повний текст джерелаLa capa límit atmosfèrica és la part més baixa de l'atmosfera terrestre on s'hi desenvolupa la vida humana. En condicions d'estratificació estable i sobre terreny no homogeni esdevé un sistema molt complex amb múltiples interaccions dels processos físics que hi tenen lloc. Per a entendre i quantificar algunes de les incerteses que planteja l'atmosfera a la capa límit en aquesta tesi principalment hem utilitzat eines de simulació numèrica. Els models numèrics permeten la comprensió més enllà de les dades experimentals, així com testejar les descripcions teòriques, a més de simular fenòmens que són molt difícils de mesurar. L'objectiu és, doncs, contribuir a la comprensió dels fenòmens que tenen lloc a la capa límit en condicions d'estratificació estable i sobre àrees de terreny complex i explorar les capacitats i les limitacions de la seva modelització numèrica. D'entre els principals resultats, fent ús del model WRF en l'aproximació de mesoscala, hem determinat l'origen d'una corrent de densitat que va donar lloc a ones de gravetat interna en la zona del Centro de Investigaciones de la Baja Atmósfera (CIBA). Hem vist que una massa d'aire amb origen de brisa marítima juntament amb els vents catabàtics originats a les cadenes muntanyoses del voltant són l'origen de la corrent de densitat que genera ones de gravetat al seu pas per l'àrea del CIBA. Per altra banda, hem explorat l'estructura vertical de la turbulència en condicions neutrals i estables fent ús del model WRF en l'aproximació LES (WRF-LES). S'han investigat els règims de intensitat de turbulència en funció de la velocitat del vent i s'ha obtingut una relació semblant a les observacions en situació de forta turbulència. Veiem les condicions de contorn del model a la superfície i al límit superior poden afectar molt significativament l'estructura dels remolins. Finalment, l'estudi de les ones de muntanya sobre la orografia complexa del Pirineu amb el model WRF en el mode mesoscalar ha permès avaluar la capacitat del model per a representar l'esdeveniment i la variació en els resultats en funció de les seves diferents opcions físiques i de configuració.
Mirocha, Jeffrey D. "An investigation of the stably-stratified atmospheric boundary layer over the Arctic Ocean during stable, clear-sky, winter conditions." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/dissertations/fullcit/3186935.
Повний текст джерелаMarti, Clelia Luisa. "Exchange processes between littoral and pelagic waters in a stratified lake." University of Western Australia. Centre for Water Research, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0005.
Повний текст джерелаCowan, Ian Robert. "Density-stratified turbulent boundary layers." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321001.
Повний текст джерелаAyet, Alex. "Flux de quantité de mouvement à l'interface air-mer : approche théorique du couplage entre turbulence et vagues de vent On the Impact of Long Wind-Waves on Near-Surface Turbulence and Momentum Fluxes, in Boundary-Layer Meteorology volume 174, March 2020 Scalewise return to isotropy in stratified boundary layer flows, in JGR Atmospheres 125 (16), August 2020 Scaling laws for the length scale of energy‐containing eddies in a sheared and thermally stratified atmospheric surface layer, in Geophysical Research Letters 47(23), December 2020." Thesis, Brest, 2020. http://www.theses.fr/2020BRES0038.
Повний текст джерелаDespite numerous works, the causal link between wind and waves is still a controversial subject. This is due, among others, to the multi-scale nature of a realistic ocean surface and to wave breaking, which changes its topology. In this thesis, such problems are studied from a theoretical perspective, using a phenomenological model linking the spectral and averaged properties of wall-bounded turbulence through the geometry attached eddies.The first part of the thesis revisits this phenomenological model by questioning its underlying assumptions and, in particular, reveals inconsistencies in the models used for the energy redistribution between turbulence components (the Rotta model). The phenomenological model is then used to study the coupling between long wind-waves (of order 10m) and turbulence. Results indicate that the deformation of attached eddies, induced by this interaction, could explain some of the variability in momentum fluxes for a given mean wind. Finally, the study of the coupling between turbulence and short breaking waves is approached by defining a roughness sublayer, in which the properties of the attached eddies depend solely on the speed of the dominant breaking fronts for a given wind. These two studies from the basis of a new paradigm to study the multi-scale coupling between the turbulent and wave spectra. This would allow accounting for the influence of environmental parameters on momentum and heat fluxes, and opens new paths both from a theoretical perspective and for the analysis of experimental data
Dall'Ozzo, Cédric. "Modélisation d'écoulements atmosphériques stratifiés par Large-Eddy Simulation à l'aide de Code_Saturne." Phd thesis, Université Paris-Est, 2013. http://pastel.archives-ouvertes.fr/pastel-00861196.
Повний текст джерелаAbraham, Carsten. "Regime occupation and transition information obtained from observable meteorological state variables in the stably stratified nocturnal boundary layer." Thesis, 2018. https://dspace.library.uvic.ca//handle/1828/10511.
Повний текст джерелаGraduate
2019-12-17
Ruscher, Paul Harold. "An examination of structure and parameterization of turbulence in the stably-stratified atmospheric boundary layer." Thesis, 1987. http://hdl.handle.net/1957/29289.
Повний текст джерелаGraduation date: 1988
Soontiens, Nancy. "Stratified Flow Over Topography: Steady Nonlinear Waves, Boundary Layer Instabilities, and Crater Topography." Thesis, 2013. http://hdl.handle.net/10012/8049.
Повний текст джерелаJheng, Jia-Jyun, and 鄭佳俊. "Correlation of Stratified VOCs Distribution with Atmospheric Temperature Inversion in the Boundary Layer of Atmosphere." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/66247106763576738013.
Повний текст джерела國立高雄海洋科技大學
海洋環境工程研究所
101
VOCs are ozone precursors that contribute to ozone air pollution. The concentration of VOCs may be affected by weather conditions in the atmosphere, which may create stratification. Past literature has proposed that mixing occurs in the inversion layer, leading to the distribution and stratification of VOCs in the atmosphere. However, ozone air quality models have long assumed that the precursor pollutants are uniformly mixed vertically; this may be a source of error for air quality models. In order to confirm that the temperature inversion phenomenon will affect the distribution of VOCs in the atmosphere, this study has monitored the vertical distribution of the concentrations of VOCs in the atmosphere and investigated the correlation with the inversion layer. The study uses the balloon sampling method which measured the temperature and collected air samples from ground level to an elevation of 800 meters and used Entech 7100A thermal desorption by the refrigeration system as pre-handling and GC/MS for the detection of VOCs. Inversion layers occur in the vertical portion of the atmosphere, where it is at a steady and stable state. However, the areas surrounding the inversion layer is not at a stable state. The results of my studies have shown that during the summer, temperature inversion occurs in the morning between 7:00 to 10:00 whereas during the winter, inversion typically occurs between 18:00 to midnight. During these two seasons at 14:00, there is a weak inversion layer near the ground. During inversion, the diffusion of VOCs and air vertically through the atmosphere is very poor. Pollutants that are trapped under the inversion layer cannot disperse into the atmosphere and accumulate near the ground. Above the inversion layer there is pollution caused by long distance transmission and the pollutants become concentrated above the inversion layer. Through POCP and MIR calculations, we found that the formation of the ozone layer will undergo stratification if temperature inversion occurs. Ozone air quality models have long assumed that the precursor pollutants are uniformly mixed vertically; this may be a source of error for AQM. Therefore, we concluded that the vertical atmosphere has an inversion layer that is caused by temperature inversion.
Kravchuk, Sergiy. "Study of abrupt transitions in two-dimensional ideal flows: a singular perturbation approach." 2006. http://arrow.unisa.edu.au/vital/access/manager/Repository/unisa:35849.
Повний текст джерела(8066834), David J. Cannon. "Hypolimnetic Mixing in Lake Michigan." Thesis, 2019.
Знайти повний текст джерелаLittle work has been done to estimate turbulence characteristics in the hypolimnetic waters of large lakes, where the magnitude and vertical structure of turbulent parameters have important implications for nutrient cycling and benthic exchange. In this thesis, hypolimnetic mixing is investigated over the annual stratification cycle in a large lake using a series of experiments in Lake Michigan that utilize acoustic Doppler velocimeters, thermistors, and microstructure profilers to characterize mean flow and turbulence throughout the water column. More than 500 days of physical limnological data were collected and analyzed over the course of this study, creating the most comprehensive data set of its kind in the Laurentian Great Lakes. While we found that bottom boundary layer turbulence and mean flow follow law-of-the-wall predictions in the mean, individual estimates were shown to deviate significantly from canonical expectations, with deviations linked to weakly energetic flow conditions (i.e. low speeds) and seiche-scale flow unsteadiness. Bottom boundary layer characteristics, including the mean current speed (U50=3 cm/s), drag coefficient (Cd50=0.0052), and turbulent kinetic energy dissipation (ϵ50 =10-8 W/kg), showed very little seasonal variation, despite highly variable surface forcing (e.g. stratification, wind speeds). Full water column turbulence profiles measured during the stratified summer were largely buoyancy suppressed, with internal Poincaré waves driving enhanced turbulent kinetic energy dissipation (ϵ= 10-7 W/kg) in the relatively compact thermocline and weak hypolimnetic mixing (turbulent scalar diffusivity: Kz=10-6 m2/s) limiting benthic nutrient delivery. Although small temperature gradients drove strong mixing over the isothermal period (Kz=10-3 m2/s), velocity shear was overwhelmed by weakly stable stratification (Richardson number:Ri≈0.2), limiting the development of the surface mixed layer and suppressing hypolimnetic turbulence (ϵ=10-9 W/kg; Kz=10-4 m2/s). When surface temperatures fell below the temperature of maximum density (TMD≈ 4℃), radiative convection played a major role in driving vertical transport, with energetic full water column mixing throughout the day followed by surface cooling and restratification overnight. During this “convective winter” period, daily temperature instabilities were directly correlated with elevated turbulence levels (ϵ=10-7 W/kg; Kz≈10-1 m2/s), and overnight turbulence characteristics were similar to those observed over the isothermal spring. Near surface dissipation and diffusivity measurements followed similarity scaling arguments, with wind shear and surface fluxes dominating production in the surface mixed layer during all three seasons. Together, these results are used to model the influence of invasive dreissenids over each forcing period, providing insight into the annual variability of effective filtration rates in the calm, hypolimnetic waters of Lake Michigan.
Venayagamoorthy, Subhas Karan. "Turbulent mixing and dispersion in environmental flows." Thesis, 2002. http://hdl.handle.net/10413/4833.
Повний текст джерелаThesis (M.Sc.Eng.)-University of Natal, Durban, 2002.
DORE, VALENTINA. "On the development of the convective boundary layer in a shear-free thermally forced stably stratified fluid setting: a 2D and 3D experimental investigation using image analysis techniques coupled with temperature measurements." Doctoral thesis, 2010. http://hdl.handle.net/11573/917808.
Повний текст джерела