Equilibrium of liquid drops under the effects of rotation and acoustic flattening: results from USML-2 experiments in Space

1998 ◽  
Vol 354 ◽  
pp. 43-67 ◽  
Author(s):  
C. P. LEE ◽  
A. V. ANILKUMAR ◽  
A. B. HMELO ◽  
T. G. WANG
Keyword(s):  
Experimental Study ◽  
Angular Velocity ◽  
Liquid Drop ◽  
Sound Field ◽  
Theoretical Models ◽  
Liquid Drops ◽  
Complementary Effect ◽  
Rotating Liquid ◽  
Neutral Equilibrium ◽  
Effects Of Rotation

Previous Space-based experiments (Wang et al. 1994a) showed that a rotating liquid drop bifurcates into a two-lobed shape at a lower critical angular velocity, if it is flattened acoustically by the leviating sound field. In this work, we undertake a systematic experimental study of the effect of acoustic flattening on the rotational bifurcation of a liquid drop. We also look into the complementary effect of rotation on the equilibrium of an acoustically drastically flattened drop. Theoretical models are developed for each of the two effects and then woven into a unified picture. The first effect concerns neutral equilibrium, while the second concerns loss of equilibrium, neither of them involving instability. The theories agree well with the experiments.

Experimental study of the oscillations of a rotating drop

1985 ◽  
Vol 158 ◽  
pp. 317-327 ◽  
Author(s):  
P. Annamalai ◽  
E. Trinh ◽  
T. G. Wang
Keyword(s):  
Experimental Study ◽  
Analytical Study ◽  
Liquid Drop ◽  
Angular Speed ◽  
Immiscible Fluid ◽  
Drop Shape ◽  
Free Decay ◽  
Resonance Frequencies ◽  
Rotating Liquid ◽  
Relative Change

Two- and three-lobed oscillations of a rotating liquid drop immersed in an immiscible fluid of comparable density and the same angular velocity were studied experimentally. Using acoustically suspended drops, it has been found that the relative change in the resonance frequencies of the axisymmetric drop-shape oscillations Δωl/ωl(0) is proportional to the square of the normalized angular speed (Ω/ωl(0))2 when ωl > 2Ω. This is in agreement with a recent analytical study of the same problem. Some preliminary results regarding the effect of rotation on the free-decay rate of the two-lobed oscillations are also presented.

scholarly journals Granular impact cratering by liquid drops: Understanding raindrop imprints through an analogy to asteroid strikes

2014 ◽  
Vol 112 (2) ◽  
pp. 342-347 ◽  
Author(s):  
Runchen Zhao ◽  
Qianyun Zhang ◽  
Hendro Tjugito ◽  
Xiang Cheng
Keyword(s):  
High Speed ◽  
Granular Media ◽  
Liquid Drop ◽  
Impact Craters ◽  
High Speed Photography ◽  
Impact Cratering ◽  
Liquid Drops ◽  
Asteroid Impact ◽  
Liquid Marble ◽  
Crater Morphology

When a granular material is impacted by a sphere, its surface deforms like a liquid yet it preserves a circular crater like a solid. Although the mechanism of granular impact cratering by solid spheres is well explored, our knowledge on granular impact cratering by liquid drops is still very limited. Here, by combining high-speed photography with high-precision laser profilometry, we investigate liquid-drop impact dynamics on granular surface and monitor the morphology of resulting impact craters. Surprisingly, we find that despite the enormous energy and length difference, granular impact cratering by liquid drops follows the same energy scaling and reproduces the same crater morphology as that of asteroid impact craters. Inspired by this similarity, we integrate the physical insight from planetary sciences, the liquid marble model from fluid mechanics, and the concept of jamming transition from granular physics into a simple theoretical framework that quantitatively describes all of the main features of liquid-drop imprints in granular media. Our study sheds light on the mechanisms governing raindrop impacts on granular surfaces and reveals a remarkable analogy between familiar phenomena of raining and catastrophic asteroid strikes.

Two-proton radioactivity within Coulomb and proximity potential model

2021 ◽  
Author(s):  
De-Xing Zhu ◽  
Hong-Ming Liu ◽  
Yang-Yang Xu ◽  
You-Tian Zou ◽  
Xi-Jun Wu ◽  
...  
Keyword(s):  
Potential Model ◽  
Liquid Drop ◽  
Theoretical Models ◽  
Parent Nucleus ◽  
Drip Line ◽  
Liquid Drop Model ◽  
Empirical Formulas ◽  
Proximity Potential ◽  
Proton Radioactivity ◽  
Good Agreement

Abstract In the present work, considering the preformation probability of the emitted two protons in the parent nucleus, we extend the Coulomb and proximity potential model (CPPM) to systematically study two-proton (2p) radioactivity half-lives of the nuclei close to proton drip line, while the proximity potential is chosen as Prox.81 proposed by Blocki et al. in 1981. Furthermore, we apply this model to predict the half-lives of possible 2p radioactive candidates whose 2p radioactivity is energetically allowed or observed but not yet quantified in the evaluated nuclear properties table NUBASE2016. The predicted results are in good agreement with those from other theoretical models and empirical formulas, namely the effective liquid drop model (ELDM), generalized liquid drop model (GLDM), Gamow-like model, Sreeja formula and Liu formula.

A complementary numerical and experimental study of the influence of Reynolds number on theoretical models for wingtip vortices

2019 ◽  
Vol 180 ◽  
pp. 176-189 ◽  
Author(s):  
J. Hermenegildo García-Ortiz ◽  
A. Domínguez-Vázquez ◽  
J.J. Serrano-Aguilera ◽  
L. Parras ◽  
C. del Pino
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Theoretical Models

Statistical and Theoretical Models of Ingestion Through Turbine Rim Seals

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Kunyuan Zhou ◽  
Simon N. Wood ◽  
J. Michael Owen
Keyword(s):  
Experimental Data ◽  
Statistical Model ◽  
Flow Parameter ◽  
Likelihood Estimation ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Data Points ◽  
Effects Of Rotation ◽  
Effectiveness Data ◽  
Good Agreement

In recent papers, orifice models have been developed to calculate the amount of ingestion, or ingress, that occurs through gas-turbine rim seals. These theoretical models can be used for externally induced (EI) ingress, where the pressure differences in the main gas path are dominant, and for rotationally induced (RI) ingress, where the effects of rotation in the wheel space are dominant. Explicit “effectiveness equations,” derived from the orifice models, are used to express the flow rate of sealing air in terms of the sealing effectiveness. These equations contain two unknown terms: Φmin, a sealing flow parameter, and Γc, the ratio of the discharge coefficients for ingress and egress. The two unknowns can be determined from concentration measurements in experimental rigs. In this paper, maximum likelihood estimation is used to fit the effectiveness equations to experimental data and to determine the optimum values of Φmin and Γc. The statistical model is validated numerically using noisy data generated from the effectiveness equations, and the simulated tests show the dangers of drawing conclusions from sparse data points. Using the statistical model, good agreement between the theoretical curves and several sets of previously published effectiveness data is achieved for both EI and RI ingress. The statistical and theoretical models have also been used to analyze previously unpublished experimental data, the results of which are included in separate papers. It is the ultimate aim of this research to apply the effectiveness data obtained at rig conditions to engine-operating conditions.

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