scholarly journals Study of Liquid Viscosity Effects on Hydrodynamic Forces on an Oscillating Circular Cylinder Underwater Using OpenFOAM®

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1806
Author(s):  
Hongfei Mao ◽  
Yanli He ◽  
Guanglin Wu ◽  
Jinbo Lin ◽  
Ran Ji
Keyword(s):  
Circular Cylinder ◽  
Hydrodynamic Forces ◽  
Liquid Viscosity ◽  
Viscous Effects ◽  
Shear Forces ◽  
Two Phase ◽  
Viscosity Effects ◽  
Viscous Shear ◽  
Frequency Components ◽  
Fluid Theory

By neglecting the viscosity of fluid and rotation in flow, the theory of potential flow cannot accurately predict the hydrodynamic forces on the structures under significant viscous effects. In this study, the effects of liquid viscosity on the hydrodynamic forces on a horizontal circular cylinder underwater with a large-amplitude forced oscillation were investigated. The study used a two-dimensional two-phase flow wave tank model based on the viscous fluid theory using the OpenFOAM® package. The numerical calculations were carried out under different types of liquid (i.e., liquid with different viscosities). The liquid viscosity effects are visually shown by comparison of the various frequency components of the hydrodynamic forces on the cylinder, and the magnitude and phase relations of the viscous shear forces and the pressure forces. By analyzing the distribution characteristics of the flow fields around the circular cylinder, the viscous-effect mechanisms are revealed. It is found that the discrepancies of the contributions of viscous shear forces, and the discrepancies of the vortex effects on the phase and magnitude of the pressure forces lead to the obvious differences among the results under different liquid viscosities.

FROUDE’S LAW OF SIMILITUDE – CONTEMPORARY AND FUTURE SEAKEEPING TESTING

2021 ◽  
Vol 153 (A2) ◽  
Author(s):  
R P Dallinga ◽  
R H M Huijsmans
Keyword(s):  
Model Test ◽  
Scale Effects ◽  
Higher Order ◽  
Air Pressure ◽  
Test Results ◽  
Viscous Effects ◽  
Two Phase ◽  
Scale Models ◽  
Non Linear

Historically “scale effects” in the interpretation of tests with scale models in waves using Froude’s Law of Similitude are mostly associated with viscous effects. Nowadays, with a much more complete modelling of reality and a focus on higher order non-linear phenomena, scaling of model test results implies a wider range of assumptions than the validity of Froude’s Law. Our contribution to the conference is a visionary review of contemporary and future problems in the interpretation of these tests. In this context we will discuss the developments in test techniques, including the development of a new Two-Phase Laboratory facilitating seakeeping and sloshing tests at reduced air pressure.

scholarly journals 419 Effect of Liquid Viscosity on Wave and Droplet Inception in Gas-Liquid Two-Phase Flow

2000 ◽  
Vol 005.2 (0) ◽  
pp. 133-134
Author(s):  
Koji MORI ◽  
Kuniaki NAKANO ◽  
Naoshi HASEGAWA ◽  
Toru HONJO
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Liquid Viscosity ◽  
Two Phase

scholarly journals Three Dimensionality of Hydrodynamic Forces on Vertical Circular Cylinder Oscillating Sinusoidally

1992 ◽  
Vol 1992 (171) ◽  
pp. 133-145
Author(s):  
Takeshi Kinoshita ◽  
Shunji Sunahara ◽  
Kuniaki Shohji
Keyword(s):  
Circular Cylinder ◽  
Hydrodynamic Forces

Empirical Correlations for Prediction Slug Liquid Holdup on Slug-Pseudo-Slug and Slug-Churn Transitions in Vertical and Inclined Two-Phase Flow

2021 ◽  
pp. 1-13
Author(s):  
Ghassan H. Abdul-Majeed ◽  
Abderraouf Arabi ◽  
Gabriel Soto-Cortes
Keyword(s):  
Two Phase Flow ◽  
Liquid Velocity ◽  
Superior Performance ◽  
Phase Flow ◽  
Liquid Viscosity ◽  
Empirical Correlations ◽  
Liquid Holdup ◽  
Two Phase ◽  
Experimental Database ◽  
Transition Models

Summary Most of the existing slug (SL) to churn (CH) or SL to pseudo-slug (PS) transition models (empirical and mechanistic) account for the effect of the SL liquid holdup (HLS). For simplicity, some of these models assume a constant value of HLS in SL/CH and SL/PS flow transitions, leading to a straightforward solution. Other models correlate HLS with different flow variables, resulting in an iterative solution for predicting these transitions. Using an experimental database collected from the open literature, two empirical correlations for prediction HLS at the SL/PS and SL/CH transitions (HLST) are proposed in this study. This database is composed of 1,029 data points collected in vertical, inclined, and horizontal configurations. The first correlation is developed for medium to high liquid viscosity two-phase flow (μL > 0.01 Pa·s), whereas the second one is developed for low liquid viscosity flow (μL ≤ 0.01 Pa·s). Both correlations are shown to be a function of superficial liquid velocity (VSL), liquid viscosity (μL), and pipe inclination angle (θ). The proposed correlations in a combination with the HLS model of Abdul-Majeed and Al-Mashat (2019) have been used to predict SL/PS and SL/CH transitions, and very satisfactory results were obtained. Furthermore, the SL/CH model of Brauner and Barnea (1986) is modified by using the proposed HLST correlations, instead of using a constant value. The modification results in a significant improvement in the prediction of SL/CH and SL/PS transitions and fixes the incorrect decrease of superficial gas velocity (VSG) with increasing VSL. The modified model follows the expected increase of VSG for high VSL, shown by the published observations. The proposed combinations are compared with the existing transition models and show superior performance among all models when tested against 357 measured data from independent studies.

Partially Cavitating Hydrofoils: Experimental and Numerical Analysis*

2000 ◽  
Vol 44 (01) ◽  
pp. 40-58
Author(s):  
Christian Pellone ◽  
Thierry Maître ◽  
Laurence Briançon-Marjollet
Keyword(s):  
Numerical Models ◽  
Lift Coefficient ◽  
Pressure Coefficient ◽  
Navier Stokes ◽  
Viscous Effects ◽  
Local Pressure ◽  
Two Phase ◽  
Complete Study ◽  
Flow Configurations ◽  
Potential Methods

The numerical modeling of partially cavitating foils under a confined flow configuration is described. A complete study of previous numerical models highlights that the presence of a turbulent and two-phase wake, at the rear of the cavity, has a nonnegligible effect on the local pressure coefficient, the cavitation number, the cavity length and the lift coefficient; hence viscous effects must be included. Two potential methods are used, each being coupled with a calculation of the boundary layer developed downstream of the cavity. So, an "open cavity" numerical model, as it is called, was developed and tested with two types of foil: a NACA classic foil and a foil of which the profile is obtained performing an inverse calculation on a propeller blade test section. On the other hand, under noncavitating conditions, for each method, the results are compared with the results obtained by the Navier-Stokes solver "FLUENT." The cavitating flow configurations presented herein were carried out using the small hydrodynamic tunnel at Bassin d'Essais des Carènes [Val de Reuil, France]. The results obtained by the two methods are compared with experimental measurements.

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