TY  - GEN
Y1  - 2017///
TI  - Modeling of Heat Exchange Across the Ocean Surface
as Measured by Active Thermography
ID  - heidok22980
A1  - Haltebourg, Clemens
N2  - A spatially and temporally instationary heat transfer equation is solved under a Neumann boundary condition that corresponds to an actively controlled heat flux onto the surface of a body of water. The partial differential equation needs to be closed by a model that specifes the structure of turbulence inside the heat boundary layer. A film model and two types of surface renewal models are studied, where for the surface renewal models closed
form solutions are derived and for the film model an approximation is given. A flow field is considered as it is expected to form within the viscous boundary layer under the action of a wind field exerting shear stress on the water surface. The solution is specialized to the spatio-temporal heat concentration field on the surface, allowing for determination of the shear momentum flux introduced by the wind field as well as the surface flow velocity
and heat transfer velocity. This is achieved by comparing the model predictions with infrared image sequences that measure the heat distribution on the water surface. Based
on theoretical results, an evaluation algorithm is developed and tested on data of laboratory measurements. Thereby it is revealed that a reliable determination of the shear momentum
flux requires a thorough selection of measurement conditions in that they are suitable for the available models. From the evaluation performed within this thesis, necessary conditions on future measurements can be derived that allow for a resilient contact-free, spatially and temporally highly resolved estimation of the shear momentum flux. The simultaneous determination of the heat transfer velocity assures that both quantities are subject to the same environmental conditions.
AV  - public
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/22980/
ER  -