Tidlegare gjesteforelesninger og seminarer - Side 94

Fredagskollokvium

By Fabien Burki.

Friday Seminar

By Thomas Cavalier-Smith.

Friday Seminar by Cedric Berney.

Fredagskollokvium

Friday Seminar

By Jørn Hurum.

Fredagskollokvium

Stratified flow phenomena are prevalent throughout the oceans. We present the results of laboratory experiments that study several ocean inspired problems, including: the settling of marine snow, spontaneous propulsion of asymmetric objects and the generation of internal wave beams by topography. These experiments cover a large range of physical scales, from as small as 100 microns for the settling of marine snow to several meters for internal wave generation, emphasizing the richness of interesting and important research problems is stratified flow

Dr. Tom Peacock of Dept. of Mechanical Engineering, MIT is a visitor at the BILAT-program. He is an expert on theoretical physics, and does currently theoretical, experimental and field work on internal waves in the ocean.

Friday Seminar by Øyvind Fiksen.

Fredagskollokvium

Friday Seminar by Eva Kisdi.

Fredagskollokvium

Fredagskollokvium

 

 

Short presentation of Shell Technology Norway, STN STN strategy and focusing areas Typical Subsea and cleaner production activities Typical RD projects A typical field development project, Ormen Lange STN RD challenges

Fredagskollokvium

In a recent Ph.D. project the possibility of applying the Discontinuous Galerkin spectral/hp element method for the next generation of Boussinesq-type models has been investigated. These numerical methods have reached a level of maturity that turns them into an attractive alternative to the existing Boussinesq-type models, which traditionally have been based on finite difference methods in structured domains. In particular, we seek to take advantage of the geometrical flexibility of spectral/hp finite element methods to enable us to solve wave problems in increasingly complex environments. A nodal discontinuous Galerkin finite element method (DG-FEM) is used for the spatial discretization to solve a recently derived set of high-order Boussinesq-type equations [1] in complex and curvilinear geometries, and thereby amends the application range of previous numerical models. The new Boussinesq method allows for the accurate description of fully nonlinear and dispersive water waves in both shallow and deep waters, and to demonstrate and investigate the applicability of the model both linear and nonlinear test cases have been considered where water waves interact with bottom-mounted fully reflecting structures. References [1] Madsen, P. A., Bingham, H. B. and Liu, H. 2002 A new Boussinesq method for fully nonlinear waves from shallow to deep water. J. Fluid Mech. 462, pp. 1-30.

Dr. Allan Engsig-Karup is at Coastal, Maritime and Structural Engineering Technical University of Denmark (DTU) Lyngby, Denmark.

Fredagskollokvium

Oljeindustrien i Norge startet opp på 70-tallet, dvs. at mange av de konstruksjoner som står i nordsjøen nå er over 30år gamle. Ny teknologi gjør at oljeselskapene kan ta ut mer olje og gass av reservoarene enn det som opprinnelig var planlagt. Dessuten finner de nye felt som utvinnes via undervannsteknologi, men som fordrer behandling på eksisterende konstruksjoner. Dette gjør at levetiden til eksisterende konstruksjoner må forlenges. Forlengelse av levetid for store komplekse konstruksjoner er en av kjernevirksomhetene til konstruksjonsavdelingen i FORCE Technology. Ved bruk av avanserte berengningsmodeller/programmer bistår vi våre kunder med å evaluere nye miljølaster (bølger, vind, strøm etc.), nye vekter og ikke minst konstruksjonens integritet som følge av disse nye endringene. Foredraget vil gi eksempler på noen prosjekter FORCE jobber med, programmer vi bruker og teorien bak noen av disse.  Vi ønsker ikke minst studenter velkommen til seminaret. Både interesserte på bachelor- og masterstudiet. Det vil være mulighet for en samtale med FORCE etter foredraget med tanke på mulig ansettelse i FORCE. Klikk herfor mer informasjon.

 

Fredagskollokvium

Fredagskollokvium

Air-sea interaction plays a vital role in modulating weather and climate from global scales down to scales of the smallest surface waves. Ultimately, the bulk parameterization of air-sea fluxes in coupled atmosphere-ocean models depends on small scale processes. In this talk I will present results of ongoing air-sea interaction research at Scripps that uses both traditional atmospheric measurements of heat flux along with infrared imaging of the sea surface to study wave-modulated heat flux and surface turbulence. These measurements were made off the Scripps Pier and from R/P FLIP off the coast of California. A second set of experiments was undertaken in the Gulf of Tehuantepec, on the Pacific coast of Mexico, which is well known for the regular occurrence of high winds in winter which blow through the mountain gap at the head of the gulf out over the Pacific. In February 2004, we conducted a 4-week campaign of airborne measurements of the development of the wave field and wind field with fetch out to approximately 500 km offshore. The primary aim of the experiment was to measure the coupled development of the wave field and wind field, including the statistics of surface wave breaking for an improved understanding of the dissipation of surface waves and their role in air-sea fluxes. We used the NSF/NCAR C130 with its standard suite of meteorological measurements, GPS dropsondes and AXBTs, along with the NASA Airborne Terrain Mapper (ATM) used as a scanning LIDAR for surface wave measurement, and a video imaging package for measuring whitecaps. I will present an overview of the experiment and the results so far pertaining to the evolution of the surface wave field, wave breaking and extreme wave statistics.

Ken Melville is professor at the Scripps Institution of Oceanography, University of California and is an international expert on air-sea interaction.

In order to secure the safety of ships travelling along the Norwegian coast, several fine-scale wave models have been applied for the most dangerous wave areas, such as the Steady State Irregular Wave Model (STwave) and a refraction model (www.met.no: kyst_og_hav). Lately, the model Simulating Waves Nearshore (SWAN) from TUDelft, The Netherlands, was employed to forecast waves in Trondheim ship lane. SWAN is a spectral wave model, similar to WAM, developed for shallow water or coastal areas by including depth-induced wave breaking, triad wave-wave interaction and an implicit numerical scheme that allows SWAN to run efficiently on high horizontal resolution. At met.no, SWAN was set up with 418x150 grid points and a 500mx500m grid cell size. It receives spectra on the outer boundaries from met.no's operational version of WAM and is driven by winds from a 4 km x 4 km atmospheric model. The model has furthermore the option to include varying current fields (refraction, blocking, and frequency shift) which we would like to test. Current fields can be obtained from an ocean or tidal model. We will present our experience with SWAN and results so far of comparing the forecasted wave parameters with those from a buoy located at Stor-Fosna in the ship lane. Acknowledgements: The work is performed in collaboration with the Norwegian Coastal Authorities (Kystverket).

Fredagskollokvium