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Foredragene våren 2011 vil normalt finne sted på mandager kl. 10.15-12.00
i seminarrom B91, 9. etg. i matematikkbygningen.
Programmet annonseres her og per epost til avdeling for mekanikk etterhvert
som det blir klart.
MEKANIKKSEMINARER VÅR 2011:
- Mandag 9/5 kl. 12.15-13.00 i fellesområdet 9. etasje NHA hus:
Love Håkansson
Muligheter i CFX / Fluent
Simulations of Fluid-Solid interactions (FSI) are becoming more common
as faster computers enables the study of larger models including both
fluids and solids. In many applications it is of significant importance
to determine the impact that a flowing fluid has on the mechanical
structure surrounding it. Vortex-induced vibrations can give structural
failure due to fatigue, but it can also produce undesired acoustic
noise. During the seminar, several examples of FSI problems and solutions
will be demonstrated. The examples include the study of flow induced
vibrations in a compressor exhaust, the dynamic flow of oil through a
filter, the impact of water waves on a submerged object, etc.
Large-eddy simulations are also advancing in the industrial CFD
society. RANS modeling has shown to be insufficient in many complex flow
situations, and LES has proven to provide answers to many fundamental
questions in turbulent flows. A brief demonstration of an example with
flow over a wing profile is presented. Using LES, it is possible to
extract valuable information regarding lift, drag, etc., but it is also
possible to visualize the turbulent structures evolving from the boundary
layer on the wing.
Love Håkansson is at EDR - Engineering Data Resources
- Mandag 28/3 kl. 12.15-13.00 i fellesområdet 9.etasje:
Murat Tutkun
Measurement of turbulence in shear flows
Turbulence is complex flow phenomenon with a wide range of scales of
motion. Even though there is advancements in measurement technologies,
the tools we use in the laboratories are often not adequate to extract
all the information necessary for understanding and characterizing this
flow. How-wire anemometry has been used by researcher for many decades
due to its high temporal resolution. Even though it has good temporal
resolution, it can only provide single point data. One also needs to be
careful while using hot-wires because it has its own limitations given
different flow configurations. In this talk, we will see some examples
of hot-wire measurements in shear flow turbulence. Namely we will look
at axisymmetric wake, turbulent boundary layers, and wake boundary layer
interactions. Each of these measurements requires different setups and
different adjustments. We will discuss what we can measure, how we can
measure, how we can calibrate and how we should interpret the
results.
Murat Tutkun is at the Defense Research Establishment (FFI) and Ecole Centrale de Lille, France
- Fredag 11/3 kl. 13.15-14.00 i fellesområdet 9.etasje:
Ilker Fer
Internal waves and vertical mixing in the Arctic Ocean
Recent findings show that moderate mixing levels typical of
mid-latitude can erode or even remove the Arctic cold halocline layer and
that internal wave induced mixing is enhanced in the absence of sea ice.
In a seasonally ice-free Arctic Ocean increased levels of mixing,
sufficient to remove the cold halocline layer, can be expected as a
result of wind energy input over large areas of open water. The ice is
then easily exposed to the relatively warm Atlantic water, possibly
leading to a strong positive feedback. I will report on insight gained
from field work conducted during the International Polar Year. Detailed
finescale and turbulence measurements were made from drifting ice in the
central Arctic and in the southern Yermak Plateau located in the Marginal
Ice Zone northwest of Svalbard. Observations are analyzed to describe the
characteristics of internal waves and turbulent mixing in the Arctic
Ocean. The role of diapycnal mixing away from abyssal plains is discussed
for the Arctic Ocean and regional heat budget and ice cover.
Ilker Fer is at the Department of Geophysics at UiB
- Mandag 7/3 kl. 12.15-13.00 i fellesområdet 9.etasje:
Erik Vanem
A Bayesian-hierarchical space-time model for significant wave height
data
This paper presents a Bayesian hierarchical space-time
stochastic model for significant wave height. The model has been fitted by
data for an area in the North Atlantic ocean and aims at describing the
temporal and spatial variability of significant wave height in this area.
It could also serve as foundation for further extensions used for
long-term prediction of significant wave height and future return periods
of extreme significant wave heights. The main model and preliminary
simulation results will be presented. Furthermore, a discussion of
possible model extensions and future work will be included.
Erik Vanem is at the Statistics division of the Department of
Mathematics at UiO
Foredrag høst 2010
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