Hydrodynamic loading of perforated disks in creeping flows

2019 ◽  
Vol 4 (8) ◽  
Author(s):  
E. F. Strong ◽  
M. Pezzulla ◽  
F. Gallaire ◽  
P. Reis ◽  
L. Siconolfi
Keyword(s):  
Hydrodynamic Loading ◽  
Creeping Flows

scholarly journals Non-Isothermal Creeping Flows in a Pipeline Network: Existence Results

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1300
Author(s):  
Evgenii S. Baranovskii ◽  
Vyacheslav V. Provotorov ◽  
Mikhail A. Artemov ◽  
Alexey P. Zhabko
Keyword(s):  
Nonlinear Boundary ◽  
Galerkin Approximation ◽  
Large Data ◽  
Temperature Dependent ◽  
Weak Formulation ◽  
Temperature Dependent Viscosity ◽  
Pipeline Network ◽  
Flux Boundary Conditions ◽  
Creeping Flows ◽  
Dependent Viscosity

This paper deals with a 3D mathematical model for the non-isothermal steady-state flow of an incompressible fluid with temperature-dependent viscosity in a pipeline network. Using the pressure and heat flux boundary conditions, as well as the conjugation conditions to satisfy the mass balance in interior junctions of the network, we propose the weak formulation of the nonlinear boundary value problem that arises in the framework of this model. The main result of our work is an existence theorem (in the class of weak solutions) for large data. The proof of this theorem is based on a combination of the Galerkin approximation scheme with one result from the field of topological degrees for odd mappings defined on symmetric domains.

scholarly journals Effect of Roughness of Mussels on Cylinder Forces from a Realistic Shape Modelling

2021 ◽  
Vol 9 (6) ◽  
pp. 598
Author(s):  
Antoine Marty ◽  
Franck Schoefs ◽  
Thomas Soulard ◽  
Christian Berhault ◽  
Jean-Valery Facq ◽  
...  
Keyword(s):  
Marine Species ◽  
Offshore Structures ◽  
Offshore Wind ◽  
Mooring Lines ◽  
Shape Modelling ◽  
Offshore Wind Turbines ◽  
Specific Effects ◽  
Hydrodynamic Loading ◽  
Floating Offshore Wind Turbines ◽  
Realistic Shape

After a few weeks, underwater components of offshore structures are colonized by marine species and after few years this marine growth can be significant. It has been shown that it affects the hydrodynamic loading of cylinder components such as legs and braces for jackets, risers and mooring lines for floating units. Over a decade, the development of Floating Offshore Wind Turbines highlighted specific effects due to the smaller size of their components. The effect of the roughness of hard marine growth on cylinders with smaller diameter increased and the shape should be representative of a real pattern. This paper first describes the two realistic shapes of a mature colonization by mussels and then presents the tests of these roughnesses in a hydrodynamic tank where three conditions are analyzed: current, wave and current with wave. Results are compared to the literature with a similar roughness and other shapes. The results highlight the fact that, for these realistic roughnesses, the behavior of the rough cylinders is mainly governed by the flow and not by their motions.

An Improved Assembling Algorithm in Boundary Elements With Galerkin Weighting Applied to Three-Dimensional Stokes Flows

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Sofia Sarraf ◽  
Ezequiel López ◽  
Laura Battaglia ◽  
Gustavo Ríos Rodríguez ◽  
Jorge D'Elía
Keyword(s):  
Boundary Element Method ◽  
Linear System ◽  
Boundary Element ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Boundary Integral ◽  
Computational Time ◽  
Creeping Flows ◽  
Order Of Magnitude ◽  
Element Method

In the boundary element method (BEM), the Galerkin weighting technique allows to obtain numerical solutions of a boundary integral equation (BIE), giving the Galerkin boundary element method (GBEM). In three-dimensional (3D) spatial domains, the nested double surface integration of GBEM leads to a significantly larger computational time for assembling the linear system than with the standard collocation method. In practice, the computational time is roughly an order of magnitude larger, thus limiting the use of GBEM in 3D engineering problems. The standard approach for reducing the computational time of the linear system assembling is to skip integrations whenever possible. In this work, a modified assembling algorithm for the element matrices in GBEM is proposed for solving integral kernels that depend on the exterior unit normal. This algorithm is based on kernels symmetries at the element level and not on the flow nor in the mesh. It is applied to a BIE that models external creeping flows around 3D closed bodies using second-order kernels, and it is implemented using OpenMP. For these BIEs, the modified algorithm is on average 32% faster than the original one.

scholarly journals A MONTE-CARLO MODEL FOR CAISSON OVERTURNING BY TSUNAMIS

2020 ◽  
pp. 1
Author(s):  
Jennifer L. Irish ◽  
Robert Weiss ◽  
Beverly Goodman-Tchernov
Keyword(s):  
Monte Carlo ◽  
Scaling Law ◽  
Monte Carlo Model ◽  
Community Resilience ◽  
Coastal Inundation ◽  
Hazard Exposure ◽  
Hydrodynamic Loading ◽  
Robust Planning

Robust planning, engineering, and design in regions exposed to coastal inundation and wave extremes are critically important for ensuring economic and community resilience. To address this need, the profession is moving toward multi-faceted, risk-based approaches based on probabilistic hazard exposure that account for uncertainty. Herein, a Monte-Carlo model for sliding and overturning of caissons under extreme hydrodynamic loading is presented. The model may be used to support risk-based analyses during caisson design as well as in the characterization of inundation extremes from contemporary hazard reconnaissance and from the geological and archaeological records. Herein, model applications are presented (1) to characterize the 2nd century AD Mediterranean tsunami that damaged the ancient harbor of Caesarea, Israel and (2) to develop a scaling law for overturning.

scholarly journals Periodic and Chaotic Orbits of Plane-Confined Micro-rotors in Creeping Flows

2015 ◽  
Vol 25 (5) ◽  
pp. 1111-1123 ◽  
Author(s):  
Enkeleida Lushi ◽  
Petia M. Vlahovska
Keyword(s):  
Chaotic Orbits ◽  
Creeping Flows

scholarly journals Hybrid simulation of a structure to tsunami loading

2019 ◽  
Vol 23 (1) ◽  
pp. 3-21
Author(s):  
Bahareh Forouzan ◽  
Dilshan SP Amarsinghe Baragamage ◽  
Koushyar Shaloudegi ◽  
Narutoshi Nakata ◽  
Weiming Wu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Tsunami Wave ◽  
Hybrid Simulation ◽  
Structural Response ◽  
Fluid Loading ◽  
Hydrodynamic Loading ◽  
Simulation Step ◽  
Displacement Based ◽  
Structural Hybrid

A new hybrid simulation technique has been developed to assess the behavior of a structure under hydrodynamic loading. It integrates the computational fluid dynamics and structural hybrid simulation and couples the fluid loading and structural response at each simulation step. The conventional displacement-based and recently developed force-based hybrid simulation approaches are adopted in the structural analysis. The concept, procedure, and required components of the proposed hybrid simulation are introduced in this article. The proposed hybrid simulation has been numerically and physically tested in case of a coastal building impacted by a tsunami wave. It is demonstrated that the force error in the displacement-based approach is significantly larger than that in the force-based approach. The force-based approach allows for a more realistic and reliable structural assessment under tsunami loading.

scholarly journals Optimal Boundary Control of Non-Isothermal Viscous Fluid Flow

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 133 ◽  
Author(s):  
Evgenii S. Baranovskii ◽  
Anastasia A. Domnich ◽  
Mikhail A. Artemov
Keyword(s):  
Control Parameters ◽  
Marginal Function ◽  
Weak Formulation ◽  
Existence Of Weak Solutions ◽  
Viscous Fluid Flow ◽  
Lower Semi ◽  
Locally Lipschitz ◽  
Creeping Flows ◽  
Flow Domain ◽  
The Mathematical Model

We study an optimal control problem for the mathematical model that describes steady non-isothermal creeping flows of an incompressible fluid through a locally Lipschitz bounded domain. The control parameters are the pressure and the temperature on the in-flow and out-flow parts of the boundary of the flow domain. We propose the weak formulation of the problem and prove the existence of weak solutions that minimize a given cost functional. It is also shown that the marginal function of this control system is lower semi-continuous.

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