The fluid mechanics of poohsticks

Cartwright, Julyan H. E.; Piro, Oreste

doi:10.1098/rsta.2019.0522

Cited by 4 publications

(4 citation statements)

References 62 publications

(87 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This study observed that the diameter of the coronary arteries was larger in patients with CSF than in those with NCSF and was associated with high CSF risk, which is consistent with previous studies ( 14 , 15 ). According to Bernoulli’s equation and Poiseuille’s law, the flow velocity of Newtonian fluids in circular-sectioned pipes decreases when the pipes abruptly enlarge28 ( 28 ). Thus, changes in cardiovascular diameter or cross-sectional area may play an important role in the pathophysiology of CSF.…”

Section: Discussionmentioning

confidence: 99%

Establishment and verification of a nomogram that predicts the risk for coronary slow flow

Yu,

Ran,

et al. 2024

Front. Endocrinol.

View full text Add to dashboard Cite

BackgroundCoronary slow flow (CSF) has gained significance as a chronic coronary artery disease, but few studies have integrated both biological and anatomical factors for CSF assessment. This study aimed to develop and validate a simple-to-use nomogram for predicting CSF risk by combining biological and anatomical factors.MethodsIn this retrospective case-control study, 1042 patients (614 CSF cases and 428 controls) were randomly assigned to the development and validation cohorts at a 7:3 ratio. Potential predictive factors were identified using least absolute shrinkage and selection operator regression and subsequently utilized in multivariate logistic regression to construct the nomogram. Validation of the nomogram was assessed by discrimination and calibration.ResultsN-terminal pro brain natriuretic peptide, high density lipoprotein cholesterol, hemoglobin, left anterior descending artery diameter, left circumflex artery diameter, and right coronary artery diameter were independent predictors of CSF. The model displayed high discrimination in the development and validation cohorts (C-index 0.771, 95% CI: 0.737-0.805 and 0.805, 95% CI: 0.757-0.853, respectively). The calibration curves for both cohorts showed close alignment between predicted and actual risk estimates, demonstrating improved model calibration. Decision curve analysis suggested high clinical utility for the predictive nomogram.ConclusionThe constructed nomogram accurately and individually predicts the risk of CSF for patients with suspected CSF and may be considered for use in clinical care.

show abstract

Section: Discussionmentioning

confidence: 99%

Establishment and verification of a nomogram that predicts the risk for coronary slow flow

Yu,

Ran,

et al. 2024

Front. Endocrinol.

View full text Add to dashboard Cite

show abstract

“…Owing to its simplicity, ease of operation, and its low cost, the falling ball method is a well‐established technique for measuring the viscosity of Newtonian fluids under ambient conditions as well as at elevated temperatures and pressures, for example, see References [6–9] for a broad spectrum of applications of the FBM. Furthermore, Brizard et al, [ 10,11 ] Sutterby [ 12 ] have discussed detailed designs, various corrections and the precision of the viscosity values for Newtonian fluids obtained by this method.…”

Section: Previous Workmentioning

confidence: 99%

Falling ball method for determining zero shear and shear‐dependent viscosity of polymeric systems: Solutions, melts, and composites

Suri

Patel

Chhabra

2022

Vinyl Additive Technology

View full text Add to dashboard Cite

The falling ball method (FBM) is one of the well‐established techniques for measuring the viscosity of Newtonian liquids at the room as well as at elevated temperatures and pressures. Owing to its simplicity and low cost, the possibility of extending its range of application to non‐Newtonian systems including virgin and filled polymer melts, composites, polymer‐solutions, and so forth, is explored here, In this work, theoretical results for the flow of power‐law fluids past a sphere have been used to extract the values of the zero‐shear viscosity and shear‐dependent viscosity in the low‐shear rate limit. The theoretical scheme outlined here has been validated by presenting comparisons with experimental results for scores of polymer solutions for which both falling sphere and rheological data are available in the literature. Indeed, the good correspondence obtained between these two independent data is encouraging and it is thus possible to use the FBM for shear‐thinning systems when the resulting Reynolds numbers are such that the flow is viscosity‐dominated, and the inertial effects are negligible. This implies that the Reynolds number should be ≤ ~1 for shear‐thinning fluids and ≤ ~10−5 for shear‐thickening fluids.

show abstract

“…Eames & Klettner [5] provide a nice derivation. The extra forces that come into play in unsteady flow about a sphere, which lead to what is now called the Maxey-Riley equation, are discussed in a companion paper in this theme issue [8]. As Eames & Klettner [5] also comment, Stokes' drag law contributed to the determination of two fundamental constants-Avogadro's number and the electron charge-and concomitantly to three Nobel Prizes in physics and one in chemistry.…”

Section: Those Circumstances Are Slow Viscous Flow-what We Would Now Call Stokes Flow-and Low Reynolds Numbersmentioning

confidence: 99%

“…Eames & Klettner [5] provide a nice derivation. The extra forces that come into play in unsteady flow about a sphere, which lead to what is now called the Maxey–Riley equation, are discussed in a companion paper in this theme issue [8].…”

mentioning

confidence: 99%

Stokes' law, viscometry, and the Stokes falling sphere clock

Cartwright

2020

Phil. Trans. R. Soc. A.

Self Cite

View full text Add to dashboard Cite

Clocks run through the history of physics. Galileo conceived of using the pendulum as a timing device on watching a hanging lamp swing in Pisa cathedral; Huygens invented the pendulum clock; and Einstein thought about clock synchronization in his Gedankenexperiment that led to relativity. Stokes derived his law in the course of investigations to determine the effect of a fluid medium on the swing of a pendulum. I sketch the work that has come out of this, Stokes drag, one of his most famous results. And to celebrate the 200th anniversary of George Gabriel Stokes’ birth I propose using the time of fall of a sphere through a fluid for a sculptural clock—a public kinetic artwork that will tell the time. This article is part of the theme issue ‘Stokes at 200 (part 2)’.

show abstract

The fluid mechanics of poohsticks

Cited by 4 publications

References 62 publications

Establishment and verification of a nomogram that predicts the risk for coronary slow flow

Establishment and verification of a nomogram that predicts the risk for coronary slow flow

Falling ball method for determining zero shear and shear‐dependent viscosity of polymeric systems: Solutions, melts, and composites

Stokes' law, viscometry, and the Stokes falling sphere clock

Contact Info

Product

Resources

About