Purpose: To describe a technique for visualizing fluid turbulence and cavitational energy created by ultrasonic phaco tips.
Setting: University Eye Clinic of Trieste, Trieste, Italy.
Methods: Generation of cavitational energy by the phaco tip was visualized using an optical test bench comprising several components. The technique uses a telescope system to expand a laser light source into a coherent, collimated beam of light with a diameter of approximately 50.0 mm. The expanded laser beam shines on the test tube containing the tip activated in a medium of water or ophthalmic viscosurgical device (OVD). Two precision optical collimators complete the optical test bench and form the system used to focus data onto a charge-coupled device television camera connected to a recorder.
Results: Images of irrigation, irrigation combined with aspiration, irrigation/aspiration, and phacosonication were obtained with the tip immersed in a tube containing water or OVD.
Conclusions: Optical image processing enabled acoustic cavitation to be visualized during phacosonication. The system is a possible means of evaluating a single phaco apparatus power setting and comparing phaco machines and techniques.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.jcrs.2004.04.042 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Transition Boundary from Laminar to Turbulent Flow of Microencapsulated Phase Change Material Slurry-Experimental Results.
Materials (Basel)
December 2024
Department of Mechanical and Power Engineering, Koszalin University of Technology, Raclawicka Street 15-17, 75-620 Koszalin, Poland.
An ice slurry or an emulsion of a phase change material (PCM) is a multiphase working fluid from the so-called Latent Functional Thermal Fluid (LFTF) group. LFTF is a fluid that uses, in addition to specific heat, the specific enthalpy of the phase change of its components to transfer heat. Another fluid type has joined the LFTF group: a slurry of encapsulated phase change material (PCM).
View Article and Find Full Text PDFA Near-Wall Methodology for Large-Eddy Simulation Based on Dynamic Hybrid RANS-LES.
Entropy (Basel)
December 2024
Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
Attempts to mitigate the computational cost of fully resolved large-eddy simulation (LES) in the near-wall region include both the hybrid Reynolds-averaged Navier-Stokes/LES (HRL) and wall-modeled LES (WMLES) approaches. This paper presents an LES wall treatment method that combines key attributes of the two, in which the boundary layer mesh is sized in the streamwise and spanwise directions comparable to WMLES, and the wall-normal mesh is comparable to a RANS simulation without wall functions. A mixing length model is used to prescribe an eddy viscosity in the near-wall region, with the mixing length scale limited based on local mesh size.
View Article and Find Full Text PDFPhysically Consistent Resolving Simulations of Turbulent Flows.
Entropy (Basel)
November 2024
Department of Mathematics and Statistics, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA.
Usually applied simulation methods for turbulent flows as large eddy simulation (LES), wall-modeled LES (WMLES), and detached eddy simulation (DES) face significant challenges: they are characterized by improper resolution variations and essential practical simulation problems given by huge computational cost, imbalanced resolution transitions, and resolution mismatch. Alternative simulation methods are described here. By using an extremal entropy analysis, it is shown how minimal error simulation methods can be designed.
View Article and Find Full Text PDFStudy on the foam production characteristics of air self-suction foam generator by jet.
Sci Rep
January 2025
Key Laboratory of Gas and Fire Control for Mines, Ministry of Education, Xuzhou, 221116, China.
Confined space fires could easily cause serious casualties and property damage, and foam is an effective means of preventing confined space fires. The existing foam generator does not have both momentum and foam expansion rate (FER) and is poorly suited to confined spaces. In order to develop a foam generator suitable for confined space fire protection, an in-depth analysis of the physical foaming characteristics of self-suction foam is required, and the structure of the foam generator is optimized accordingly.
View Article and Find Full Text PDFKolmogorov-Hinze Scales in Turbulent Superfluids.
Phys Rev Lett
December 2024
Department of Engineering Science, University of Electro-Communications, Tokyo 182-8585, Japan.
When a two-component mixture of immiscible fluids is stirred, the fluids are split into smaller domains with more vigorous stirring. We numerically investigate the sizes of such domains in a fully developed turbulent state of a two-component superfluid stirred with energy input rate ε. For the strongly immiscible condition, the typical domain size is shown to be proportional to ε^{-2/5}, as predicted by the Kolmogorov-Hinze theory in classical fluids.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!