| dc.contributor.advisor | Moláček, Jan Dr. | |
| dc.contributor.author | Bertens, Augustinus Cornelis Maria | |
| dc.date.accessioned | 2021-11-18T08:49:21Z | |
| dc.date.available | 2021-11-25T00:50:04Z | |
| dc.date.issued | 2021-11-18 | |
| dc.identifier.uri | http://hdl.handle.net/21.11130/00-1735-0000-0008-598E-5 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-8925 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-8925 | |
| dc.language.iso | eng | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 571.4 | de |
| dc.title | Experimental investigation of cloud droplet dynamics at the research station Schneefernerhaus | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Moláček, Jan Dr. | |
| dc.date.examination | 2021-06-17 | |
| dc.description.abstracteng | The collision–coalescence of droplets in turbulence is responsible for
the fast growth of cloud droplets from 15 to
40 μm in radius, but how exactly it causes this quick
growth is not understood. The growth of cloud droplets through
collision–coalescence is governed by two quantities: the radial
distribution function (RDF), which is a measure for the degree of
clustering the droplets exhibit, and the radial relative velocity (RRV),
which is a measure for the velocity difference between nearby droplets.
In this thesis an in-situ experiment is described, that is designed to
simultaneously measure all aspects relevant to turbulent
collision–coalescence of cloud droplets: droplet motions, droplet
sizes, and properties of the turbulent carrier flow. The experiment is
located in the German Alps, on top of the environmental research station
Schneefernerhaus, at an altitude of 2650 m where clouds
naturally occur. Droplet motions are measured using a particle tracking
setup; turbulence statistics are measured with a sonic anemometer that
is mounted close by.
Droplet sizes are measured using a novel technique that relies only on
the droplet intensities as recorded by the particle tracking experiment.
A complete derivation of the technique based on Lorentz-Mie scattering
theory is given. Droplet sizes measured with this approach are compared
to those obtained with a holographic instrument.
The experiment is used to measure droplet rms accelerations and the
radial distribution function conditioned on (pairs of) Stokes numbers.
Both qualitatively agree with literature values, but further research is
needed to see why there is no quantitative agreement.
<p>This work was supported by the European Union Horizon 2020 program, in particular Marie Skłodowska-Curie actions under Grant Agreement No. 675675."</p> | de |
| dc.contributor.coReferee | Dillmann, Andreas Prof. Dr. | |
| dc.subject.eng | fluid dynamics | de |
| dc.subject.eng | clouds | de |
| dc.subject.eng | turbulence | de |
| dc.subject.eng | particle tracking | de |
| dc.subject.eng | particles in turbulence | de |
| dc.subject.eng | experiment | de |
| dc.subject.eng | particle sizing | de |
| dc.subject.eng | turbulence statistics | de |
| dc.subject.eng | radial distribution function | de |
| dc.subject.eng | droplet sizing | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-21.11130/00-1735-0000-0008-598E-5-3 | |
| dc.affiliation.institute | Göttinger Graduiertenschule für Neurowissenschaften, Biophysik und molekulare Biowissenschaften (GGNB) | de |
| dc.subject.gokfull | Physik (PPN621336750) | de |
| dc.description.embargoed | 2021-11-25 | |
| dc.identifier.ppn | 1777984513 | |