Experimental Validation of Falling Liquid Film Models: Velocity Assumption and Velocity Field Comparison

This publication focuses on the experimental validation of film models by comparing constructed and experimental velocity fields based on model and elementary experimental data. The film experiment covers Kapitza numbers Ka = 278.8 and Ka = 4538.6, a Reynolds number range of 1.6–52, and disturbance frequencies of 0, 2, 5, and 7 Hz. Compared to previous publications, the applied methodology has boundary identification procedures that are more refined and provide additional adaptive particle image velocimetry (PIV) method access to synthetic particle images. The experimental method was validated with a comparison with experimental particle image velocimetry and planar laser induced fluorescence (PIV/PLIF) results, Nusselt’s theoretical prediction, and experimental particle tracking velocimetry (PTV) results of flat steady cases, and a good continuity equation reproduction of transient cases proves the method’s fidelity. The velocity fields are reconstructed based on different film flow model velocity profile assumptions such as experimental film thickness, flow rates, and their derivatives, providing a validation method of film model by comparison between reconstructed velocity experimental data and experimental velocity data. The comparison results show that the first-order weighted residual model (WRM) and regularized model (RM) are very similar, although they may fail to predict the velocity field in rapidly changing zones such as the front of the main hump and the first capillary wave troughs.

Labs, Lives, Technoscience

This chapter looks at Sharon Traweek's classic study of physicists, which tracks the way the experimental particle physics community reproduces itself through the training of novices. It identifies the patterns through which education and inculcation occur, and by which particle physicists learn the criteria for a successful career. It also examines the images Traweek conveys of community, stability, and gendered reproduction that can be discerned only within a sufficiently entrenched discipline. The chapter describes synthetic biology as an unstable and ambiguously bounded field in which idiosyncratic individual paths are figured prominently, especially for members of the first generation of practitioners whose training took place within the reproductive mechanisms of established disciplines. It explores paths that are embedded with different concepts and logics within the synthetic organisms that were made in different labs.

Noble liquid calorimetry at the LHC and prospects of its application in future collider experiments

Calorimetry is an important measurement technique in experimental particle physics. Although calorimeters based on liquefied noble gases were first proposed 50 years ago, they continue to play an important role in modern particle physics and have substantially contributed to the discovery of the Higgs boson at the Large Hadron Collider (LHC) at CERN in 2012.

Higgs on the Moon

Adam Falkowski reviews recent results from the Large Hadron Collider and what they should mean for the future of experimental particle physics. Learning from the history of manned spaceflight, he argues, precision experiments, not larger colliders, hold more promise.

Experimental particle paths and drift velocity in steep waves at finite water depth

The Lagrangian paths, horizontal Lagrangian drift velocity, $U_{L}$, and the Lagrangian excess period, $T_{L}-T_{0}$, where $T_{L}$ is the Lagrangian period and $T_{0}$ the Eulerian linear period, are obtained by particle tracking velocimetry (PTV) in non-breaking periodic laboratory waves at a finite water depth of $h=0.2~\text{m}$, wave height of $H=0.49h$ and wavenumber of $k=0.785/h$. Both $U_{L}$ and $T_{L}-T_{0}$ are functions of the average vertical position of the paths, $\bar{Y}$, where $-1<\bar{Y}/h<0$. The functional relationships $U_{L}(\bar{Y})$ and $T_{L}-T_{0}=f(\bar{Y})$ are very similar. Comparisons to calculations by the inviscid strongly nonlinear Fenton method and the second-order theory show that the streaming velocities in the boundary layers below the wave surface and above the fluid bottom contribute to a strongly enhanced forward drift velocity and excess period. The experimental drift velocity shear becomes more than twice that obtained by the Fenton method, which again is approximately twice that of the second-order theory close to the surface. There is no mass flux of the periodic experimental waves and no pressure gradient. The results from a total number of 80 000 experimental particle paths in the different phases and vertical positions of the waves show a strong collapse. The particle paths are closed at the two vertical positions where $U_{L}=0$.