@article {hering1998,
	title = {Particle tracking velocimetry beneath water waves. part II : water waves},
	journal = {Exp. Fluids},
	volume = {24},
	number = {1},
	year = {1998},
	pages = {10-16},
	abstract = {Particle Tracking techniques described earlier in the first part of this paper (Hering et al. 1997) were used to study the flow field beneath mechanically generated and wind induced flow fields. Experiments were conducted at three different wind/wave facilities (Heidelberg, Delft and San Diego). Particle Tracking allows an extensive study of drift velocities, wave orbital motion and turbulent Reynolds Stress beneath water waves. Monte Carlo simulations show, that the effects of the moving water surface on the calculation of mean properties of a flow can easily be avoided by Lagrangian measurements. Due to micro-scale wave breaking friction velocity profiles show a significant increase of turbulence towards the interface.},
	doi = {10.1007/s003480050145},
	author = {Frank Hering and Dietmar Wierzimok and Carsten Leue and Bernd J{\"a}hne}
}
@article {hering1997a,
	title = {Particle tracking velocimetry beneath water waves. Part I: visualization and tracking algorithms},
	journal = {Exp. Fluids},
	volume = {23},
	number = {6},
	year = {1997},
	pages = {472--482},
	abstract = {A novel particle tracking system working with a high particle concentration for the measurement of flow fields beneath water waves is described. It features a 1-4 cm thick light sheet parallel to the main wave propagation direction so that the seeding particles stay long enough in the illuminated area to enable tracking over several wave periods. An area of up to 14.0x10.0 cm2 is observed by a CCD camera with up to 200 fields/s. The polychromatic scattering theory of small particles in a light sheet illumination is investigated, enabling the segmentation of individual particles at high particle concentration.},
	doi = {10.1007/s003480050137},
	author = {Frank Hering and Dietmar Wierzimok and Carsten Leue and Bernd J{\"a}hne}
}
@conference {hering1996b,
	title = {Combined wave and flow field visualization for investigation of short-wave/long-wave interaction},
	booktitle = {Proc.\ The Air-Sea Interface, Radio and Acoustic Sensing, Turbulence and Wave Dynamics, Marseille, 24--30. June 1993},
	year = {1996},
	pages = {133--138},
	publisher = {RSMAS, University of Miami},
	organization = {RSMAS, University of Miami},
	doi = {10.5281/zenodo.14002},
	author = {Frank Hering and Dietmar Wierzimok and W. K. Melville and Bernd J{\"a}hne},
	editor = {M. A. Donelan and W. H. Hui and W. J. Plant}
}
@conference {hering1995d,
	title = {Enhanced turbulence beneath short wind-induced water waves as derived from Lagrangian flow fields},
	booktitle = {IAPSO Proceedings, XXI General Assembly, Honolulu, Hawai, August 1995, PS-10 Spatial Structure of Short Ocean Waves},
	number = {19},
	year = {1995},
	pages = {386},
	abstract = {Breaking waves and wind stress are a primary source for near-surface turbulence. Particle Tracking Velocimetry (PTV) was used developed to study turbulence beneath short wind-induced waterwaves at the circular wind-wave facility of the Institute for Environmental Physics. A thick light sheet (1-4 cm) was applied to illuminate small polystyrol seeding particles. The depth of the light sheet was chosen such that the particles stay long enough in the illuminated area to enable tracking over several wave periods. The flow field is observed by a digital CCD camera. Recording image sequences at up to 200 Hz allow an extensive study of the flow field. An automatic tracking algorithm was developed for the evaluation of the trajectories. Lagrangian flow field measurements offer an ideal approach to the study of drift profiles in the turbulent wave region, in addition yielding the thickness of that layer. Also bulk velocity and surface velocities can be derived. A measure for the turbulence was gained by the calculation of the friction velocity profile by correlating horizontal and vertical velocity components (eddy correlation technique). These profiles show a very interesting behavior. While the friction velocity profile is constant in the bulk, an abrupt enhancement of Reynolds stress from the bulk towards the water surface up to a factor of 10 is observed. The enhanced dissipation of kinetic energy beneath strong-breaking surface waves under fetch conditions was measured at Lake Ontario. Here, an enhancement dissipation factor of 5-60 was found. Our measurements now indicate that micro-scale wave breaking is sufficient to produce significant turbulence enhancement. This result contributes significantly to the understanding of gas exchange through the aqueous boundary layer and indicates that wave/turbulence interaction deserves further more detailed attention.},
	author = {Frank Hering and Dietmar Wierzimok and Bernd J{\"a}hne}
}
@conference {hering1995c,
	title = {Flow- and wave-fields associated with micro-scale wave breaking as measured simultaneously by particle tracking and wave slope visualization},
	booktitle = {IAPSO Proceedings, XXI General Assembly, Honolulu, Hawai, August 1995, PS-10 Spatial Structure of Short Ocean Waves},
	number = {19},
	year = {1995},
	pages = {385},
	abstract = {Longuet-Higgins predicted the development of a capillary roller at the crest of a short gravity wave, being the consequence of the existence of parasitic capillaries, (Capillary rollers and bores, J. Fluid Mech, Jan. 1992). According to the theory any free surface, at which the tangential stress vanishes, a surface vorticity is produced. The mean vorticity at the edge of the Stokes layer is of the order of 2(ak) f, ak being the slope and f the radian frequency of the wave. Hence capillary waves, with a high value of a are accompanied by particular large vorticity feeding the vortex roler at the crest of a short gravity wave. This phenomenon has been investigated at the circular facility of the Institute for Environmental Physics. At the same location, simultaneous time series of wave slope images and the Lagrangian flow field were obtained using an integrated optical set-up, including particle-tracking and wave-slope instruments. The particle tracking measurement yields drift- and bulk-velocities, Reynold stresses and the vorticity distribution beneath the wave, while the imaging wave slope gauges gives the 2D-slope and the height of the waves. First results from the measurement campaign of early 1995 will be presented.},
	author = {Frank Hering and G{\"u}nther Balschbach and M. Menzel and Dietmar Wierzimok and Bernd J{\"a}hne}
}
@conference {hering1995b,
	title = {Measurements of enhanced turbulence in short wind-induced water waves},
	booktitle = {Air-Water Gas Transfer, Selected Papers, 3rd Intern. Symp. on Air-Water Gas Transfer},
	year = {1995},
	pages = {775--784},
	publisher = {AEON},
	organization = {AEON},
	doi = {10.5281/zenodo.10328},
	author = {Frank Hering and Dietmar Wierzimok and Bernd J{\"a}hne and Bernd J{\"a}hne},
	editor = {E. C. Monahan}
}
@conference {hering1995a,
	title = {Particle tracking in space time sequences},
	booktitle = {Computer Analysis of Images and Patterns},
	volume = {970},
	year = {1995},
	pages = {294--301},
	publisher = {Springer},
	organization = {Springer},
	abstract = {A particle tracking technique at high particle concentration for the evaluation of flow fields beneath water waves is described. A 1-4 cm thick light sheet parallel to the main wave propagation direction was used to illuminate small polystyrol seeding particles. The depth of the light sheet was chosen such that the particles stay long enough in the illuminated area to enable tracking. An area of up to 14.0x10.0 cm2 is observed by a CCD camera. An automatic tracking algorithm is described to 800 particles/image, yielding both Lagrangian and Eulerian vector field. Test measurements show that the standard deviation for the velocity estimation is below 3\%.},
	doi = {10.1007/3-540-60268-2_309},
	author = {Frank Hering and Merle, M. and Dietmar Wierzimok and Bernd J{\"a}hne}
}
@conference {hering1995,
	title = {A robust technique for tracking particles over long image sequences},
	booktitle = {Proc. ISPRS Intercommission Workshop {\textquoteleft}From Pixels to Sequences{\textquoteright}, Zurich, March 22 - 24, 1995, In Int{\textquoteright}l Arch. of Photog. and Rem. Sens.},
	volume = {XXX-5W1},
	year = {1995},
	pages = {74--79},
	publisher = {RISC Books},
	organization = {RISC Books},
	doi = {10.5281/zenodo.14890},
	author = {Frank Hering and Merle, M. and Dietmar Wierzimok and Bernd J{\"a}hne},
	editor = {Baltsavias, E. P.}
}
@conference {wierzimok1993,
	title = {Quantitative imaging of transport in fluids with digital particle tracking velocimetry},
	booktitle = {Imaging in Transport Processes},
	year = {1993},
	pages = {297--308},
	publisher = {Begell House Publishers},
	organization = {Begell House Publishers},
	url = {http://www.dl.begellhouse.com/references/1bb331655c289a0a,36adf33e6f249361.html},
	author = {Dietmar Wierzimok and Frank Hering},
	editor = {S. Sideman and K. Hijikata}
}
@article {jaehne1993f,
	title = {Wellenamplitudenmessungen mittels videometrischer Bildverarbeitung},
	journal = {Mitteilungsblatt der Bundesanstalt f{\"u}r Wasserbau},
	volume = {70},
	year = {1993},
	pages = {27--62},
	author = {Bernd J{\"a}hne and H.-J. K{\"o}hler and Ralf Rath and Dietmar Wierzimok}
}
@conference {wierzimok1992,
	title = {Tracking in Str{\"o}mungsbildfolgen},
	booktitle = {Proc. 14. DAGM-Symposium Mustererkennung},
	year = {1992},
	publisher = {Springer},
	organization = {Springer},
	doi = {10.1007/978-3-642-77785-1_19},
	author = {Dietmar Wierzimok and Frank Hering and Frank Brunswig},
	editor = {Fuchs, S. and Hoffmann, R.}
}
@conference {wierzimok1991,
	title = {Measurement of wave-induced turbulent flow structure using digital image sequence analysis},
	booktitle = {Air-Water Mass Transfer, selected papers from the 2nd International Symposium on Gas Transfer at Water Surfaces, September 11--14, 1990, Minneapolis, Minnesota},
	year = {1991},
	pages = {200--209},
	publisher = {ASCE},
	organization = {ASCE},
	doi = {10.5281/zenodo.12206},
	author = {Dietmar Wierzimok and Bernd J{\"a}hne},
	editor = {Wilhelms, S. C. and John S. Gulliver}
}
@conference {wierzimok1990a,
	title = {Automatic particle tracking beneath a wind-stressed wavy water surface with image processing},
	booktitle = {Proc.\ 5th Int. Symposium Flow Visualization, Praque 1989},
	year = {1990},
	pages = {943--956},
	doi = {dx.doi.org/10.5281/zenodo.14004},
	author = {Dietmar Wierzimok and Bernd J{\"a}hne}
}
@phdthesis {wierzimok1990,
	title = {Messung turbulenter Str{\"o}mungen unterhalb der windwellenbewegten Wasseroberfl{\"a}che mittels digitaler Bildverarbeitung},
	year = {1990},
	publisher = {Institut f{\"u}r Umweltphysik, Fakult{\"a}t f{\"u}r Physik und Astronomie, Univ.\ Heidelberg},
	url = {http://d-nb.info/910573255},
	author = {Dietmar Wierzimok}
}
@conference {wierzimok1989,
	title = {Automatic particle tracking velocimetry beneath a wind-stressed wavy water surface with image processing},
	booktitle = {5th International Symposium on Flow Visualization},
	year = {1989},
	doi = {10.5281/zenodo.14004},
	author = {Dietmar Wierzimok and Bernd J{\"a}hne}
}
@conference {wierzimok1987,
	title = {Bildfolgenanalyse dreidimensionaler turbulenter Str{\"o}mungen},
	booktitle = {Proc. 9. DAGM-Symposium zur Mustererkennung 1987},
	volume = {149},
	year = {1987},
	pages = {288},
	publisher = {Springer},
	organization = {Springer},
	doi = {10.1007/978-3-662-22205-8_71},
	author = {Dietmar Wierzimok and Bernd J{\"a}hne and J. Dengler},
	editor = {E. Paulus}
}
