Fluid Dynamic Loading on Curved Riser Pipes

2003 ◽  
Vol 125 (3) ◽  
pp. 176-182 ◽  
Author(s):  
Anthi Miliou ◽  
Spencer J. Sherwin ◽  
J. Michael R. Graham
Keyword(s):  
Dynamic Loading ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Imperial College ◽  
Computational Results ◽  
Flow Conditions ◽  
Towing Tank ◽  
Riser Pipe ◽  
Flow Directions ◽  
Three Dimensional Simulations

In order to gain a preliminary understanding of the fluid dynamics developed past a curved riser pipe, a numerical investigation into the flow past curved cylinders at a Reynolds number of 100 has been performed. To approximate the flow conditions on curved riser pipes, different velocity profiles and flow directions were applied and the corresponding results compared. In addition, the fluid dynamic loading and the wake structures for curved cylinder flows were investigated. The fully three-dimensional simulations were computed with a spectral/hp element method. The computational results were compared with experiments undertaken in the towing tank facility of the Department of Aeronautics of Imperial College.

Three-Dimensional Wakes of Curved Pipes

2002 ◽  
Author(s):  
Anthi Miliou ◽  
Spencer J. Sherwin ◽  
J. Michael R. Graham
Keyword(s):  
Vortex Shedding ◽  
Stream Flow ◽  
Free Stream ◽  
Three Dimensional ◽  
Imperial College ◽  
Flow Conditions ◽  
Towing Tank ◽  
Curved Pipes ◽  
Flow Vector ◽  
Three Dimensional Simulations

A numerical investigation into the flow past curved pipes has been performed. The first group of computations includes curved pipes for which the incoming flow vector is normal to the plane of curvature. For the second group of computations the free-stream flow vector is parallel to the plane of curvature. Different flow conditions have been applied and the corresponding results compared. The vortex shedding patterns and the wake topology are studied and the sectional forces at different locations of the span are also presented. The fully three-dimensional simulations were computed with a spectral/hp element method. The computational results were compared with visualisation experiments undertaken in the towing tank facility of the Department of Aeronautics of Imperial College.

Inviscid-Viscous Coupled Solution for Unsteady Flows Through Vibrating Blades: Part 2—Computational Results

1993 ◽  
Vol 115 (1) ◽  
pp. 101-109 ◽  
Author(s):  
L. He ◽  
J. D. Denton
Keyword(s):  
Unsteady Flow ◽  
Transonic Flow ◽  
Three Dimensional ◽  
Unsteady Flows ◽  
Computational Results ◽  
Flow Conditions ◽  
Viscous Effects ◽  
Blade Flutter ◽  
Coupled Solution

A quasi-three-dimensional inviscid-viscous coupled approached has been developed for unsteady flows around oscillating blades, as described in Part 1. To validate this method, calculations for several steady and unsteady flow cases with strong inviscid-viscous interactions are performed, and the results are compared with the corresponding experiments. Calculated results for unsteady flows around a biconvex cascade and a fan tip section highlight the necessity of including viscous effects in predictions of turbomachinery blade flutter at transonic flow conditions.

Effective Particle Size Representation for Erosion Wear in Centrifugal Pump Casings

2017 ◽  
Author(s):  
Krishnan V. Pagalthivarthi ◽  
John M. Furlan ◽  
Robert J. Visintainer
Keyword(s):  
Particle Size ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Computation Time ◽  
Particle Simulation ◽  
Computational Time ◽  
Two Dimensional ◽  
Wide Range ◽  
Dimensional Simulation ◽  
Three Dimensional Simulations

For the purpose of Computational Fluid Dynamic (CFD) simulations, the broad particle size distribution (PSD) encountered in industrial slurries is classified into a discrete number of size classes. Since mono-size simulations consume much less computational time, especially in 3D simulations, it would be advantageous to determine an equivalent single particle size representation which yields the same wear distribution predictions as the multi-size simulations. This work extends the previous two-dimensional study [1], which was for a specific PSD slurry flow through three selected pumps, to determine an effective equivalent mono-size representation. The current study covers two-dimensional simulations over a wide range of pumps of varying sizes (40 pumps), 2 inlet concentrations and 4 different particle size distributions. Comparison is made between the multi-size wear prediction and different possible representative mono-size particle wear predictions. In addition, a comparison of multi-size and different mono-size results using three dimensional simulations is also shown for a typical slurry pump as a sample case to highlight that the conclusions drawn for two dimensional simulation could hold good for three dimensional simulations as well. It is observed that by using a mono-size equivalent, the computation time is 20–25% of the computation time for multi-size (6-particle) simulation.

Validation of a Time Dependent Physio-Chemical Model for Thrombus Formation and Growth

2016 ◽  
Author(s):  
Hamid Hosseinzadegan ◽  
Danesh K. Tafti
Keyword(s):  
Growth Rate ◽  
Continuum Model ◽  
Thrombus Formation ◽  
Three Dimensional ◽  
Large Species ◽  
Flow Conditions ◽  
Numerical Studies ◽  
Computational Fluid Dynamics Cfd ◽  
Acceptable Agreement ◽  
Three Dimensional Simulations

In this study, a shear-dependent continuum model for platelet activation, adhesion and aggregation is validated using computational fluid dynamics (CFD). To take the presence of red cells into account, a combination of excess-platelet boundary layer and enhanced mass diffusivity of platelets and large species is used to mimic this behavior. The model has been validated under three different shear conditions and two different heparin levels. Also three-dimensional simulations were carried out to evaluate the model’s prediction of thrombus growth rate for stenosed tubes under various flow conditions and stenosis degrees. For these cases, also the effect of change in platelet diffusivity has been investigated by using an empirical correlation for enhanced diffusivity of platelets. For all 3D simulations, results for thrombus growth rate as a function of local wall shear rate were compared to those of experiments and numerical studies in the literature and an acceptable agreement was achieved.

scholarly journals Coupled Fluid–Solid Numerical Simulation for Flow Field Characteristics and Supporting Performance of Flexible Support Cylindrical Gas Film Seal

Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Junfeng Sun ◽  
Meihong Liu ◽  
Zhen Xu ◽  
Taohong Liao ◽  
Xiangping Hu ◽  
...  
Keyword(s):  
Flow Field ◽  
Film Thickness ◽  
Fluid Dynamic ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
High Rotational Speed ◽  
Flexible Support ◽  
Flow Field Characteristics

A new type of cylindrical gas film seal (CGFS) with a flexible support is proposed according to the working characteristics of the fluid dynamic seal in high-rotational-speed fluid machinery, such as aero-engines and centrifuges. Compared with the CGFS without a flexible support, the CGFS with flexible support presents stronger radial floating characteristics since it absorbs vibration and reduces thermal deformation of the rotor system. Combined with the structural characteristics of a film seal, an analytical model of CGFS with a flexible wave foil is established. Based on the fluid-structure coupling analysis method, the three-dimensional flow field of a straight-groove CGFS model is simulated to study the effects of operating and structural parameters on the steady-state characteristics and the effects of gas film thickness, eccentricity, and the number of wave foils on the equivalent stress of the flexible support. Simulation results show that the film stiffness increases significantly when the depth of groove increases. When the gas film thickness increases, the average equivalent stress of the flexible support first decreases and then stabilizes. Furthermore, the number of wave foils affects the average foils thickness. Therefore, when selecting the number of wave foils, the support stiffness and buffer capacity should be considered simultaneously.

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