Numerical simulation of three-dimensional velocity fields in pressurized and non-pressurized Nye channels

AbstractChannels incised into bedrock, or Nye channels, often form an important component of subglacial drainage at temperate glaciers, and their structure exerts control over patterns and rates of (a) channel erosion, (b) water flow-velocity and (c) water pressure. The latter, in turn, exerts a strong control over basal traction and, thus, ice dynamics. In order to investigate these controls, it is necessary to quantify detailed flow processes in subglacial Nye channels. However, it is effectively impossible to acquire such measurements from fully pressurized, subglacial channels. To solve this problem, we here apply a three-dimensional, finite-volume solution of the Reynolds averaged Navier– Stokes (RANS) equations with a one-equation mixing-length turbulence closure to simulate flow in a 3 m long section of an active Nye channel located in the immediate foreground of Glacier de Tsanfleuron, Switzerland. Numerical model output permits high-resolution visualization of water flow through the channel reach, and enables evaluation of the experimental manipulation of the pressure field adopted across the overlying ice lid. This yields an increased theoretical understanding of the hydraulic behaviour of Nye channels, and, in the future, of their effect on glacier drainage, geomorphology and ice dynamics.

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Numerical Study on Effects of the Embedded Monopile Foundation on Local Wave-Induced Porous Seabed Response

Mathematical Problems in Engineering ◽

10.1155/2015/184621 ◽

2015 ◽

Vol 2015 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Chi Zhang ◽

Qingyang Zhang ◽

Zaitian Wu ◽

Jisheng Zhang ◽

Titi Sui ◽

...

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Numerical Study ◽

Water Pressure ◽

Three Dimensional ◽

Navier Stokes ◽

Stokes Wave ◽

Local Concentration ◽

Soil Stress ◽

Local Wave

Effects of the embedded monopile foundation on the local distributions of pore water pressure, soil stresses, and liquefaction are investigated in this study using a three-dimensional integrated numerical model. The model is based on a Reynolds-Averaged Navier-Stokes wave module and a fully dynamic poroelastic seabed module and has been validated with the analytical solution and experimental data. Results show that, compared to the situation without an embedded foundation, the embedded monopile foundation increases and decreases the maximum pore water pressure in the seabed around and below the foundation, respectively. The embedded monopile foundation also significantly modifies the distributions of the maximum effective soil stress around the foundation and causes a local concentration of soil stress below the two lower corners of foundation. A parametric study reveals that the effects of embedded monopile foundation on pore water pressure increase as the degrees of saturation and soil permeability decrease. The embedded monopile foundation tends to decrease the liquefaction depth around the structure, and this effect is relatively more obvious for greater degrees of saturation, greater soil permeabilities, and smaller wave heights.

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Implementasi Metode Elemen Hingga Untuk Persoalan Aliran Air Pada Jaringan Pipa

Talenta Conference Series Science and Technology (ST) ◽

10.32734/st.v1i1.190 ◽

2018 ◽

Vol 1 (1) ◽

Author(s):

Cici Hayani ◽

Tulus Tulus ◽

Sawaluddin Sawaluddin

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Water Flow ◽

Linear Interpolation ◽

Navier Stokes ◽

The Finite Element Method ◽

Navier Stokes Equation ◽

Water Flow Velocity ◽

Boundary Field ◽

Element Method

Pada zat cair yang mengalir di dalam bidang batas (contohnya pipa) akan terjadi tegangan geser dan gradien kecepatan pada seluruh medan aliran karena adanya kekentalan (viskositas). Penelitian ini bertujuan untuk melihat persoalan aliran air pada jaringan pipa yang diselesaikan dengan mengimplementasikan metode elemen hingga pada persamaan Navier-Stokes yang merupakan persamaan diferensial dasar yang menggambarkan aliran dari fluida Newtonian tak mampu-mampat. Dalam metode elemen hingga, medan aliran dipecah menjadi sekumpulan elemen-elemen fluida kecil (diskritisasi domain). Dalam penelitian ini peneliti menggambarkan aliran air pada bidang dua-dimensi (2D), kemudian dipilih fungsi interpolasi linier untuk elemen 2D, dan menurunkan elemen matriks dan vektor dengan metode Galerkin untuk mendapatkan persamaan Global. Hasil dari penelitian dengan bantuan komputer, memperlihatkan distribusi tekanan dan kecepatan aliran air untuk beberapa variasi bentuk pipa, yaitu pipa I dan pipa T, masing-masing juga dengan variasi posisi inlet/oulet. Hasil simulasi dengan COMSOL menunjukkan, bahwa terdapat hubungan antara tekanan dan kecepatan aliran air, kehilangan tekanan pada salah satu cabang pipa menyebabkan kecepatan aliran air menjadi tidak merata. In liquid that flows inside the boundary field (e.g., pipe) there will be shear stress and velocity gradient in all flow fields due to viscosity. This study aimed to look at the problem of water flow in the pipe network solved by implementing the finite element method in the Navier-Stokes equation. This equation is a basic differential equation that describes the flow of incompressible Newtonian fluid. In the finite element method, the flow field is broken down into a set of small fluid elements (domain discretization). In this study the researcher described the flow of water in two-dimensional (2D) fields; then linear interpolation functions for 2D elements were selected and lowered the matrix and vector elements with the Galerkin method to obtain the Global equation. The results of the study with the help of computers showed the distribution of pressure and velocity of water flow for several variations in the shape of the pipe, namely pipe I and pipe T, each also with variations in position of inlet/outlet. The simulation with COMSOL showed that there was a relationship between the pressure and velocity of water flow, and the pressure loss on one of the pipe branches caused the water flow velocity to be uneven.

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Ponded infiltration into soil with biopores — field experiment and modeling

Biologia ◽

10.2478/s11756-009-0078-7 ◽

2009 ◽

Vol 64 (3) ◽

Cited By ~ 8

Author(s):

Michal Dohnal ◽

Jaromír Dušek ◽

Tomáš Vogel ◽

Milena Císlerová ◽

Ľubomír Lichner ◽

...

Keyword(s):

Water Flow ◽

Preferential Flow ◽

Water Pressure ◽

Three Dimensional ◽

Detailed Knowledge ◽

Dye Tracer ◽

Simulation Based ◽

Flow Through ◽

Flow Effects ◽

Infiltration Experiment

AbstractPreferential movement of water in macropores plays an important role when the process of ponded infiltration in natural porous systems is studied. For example, the detailed knowledge of water flow through macropores is of a major importance when predicting runoff responses to rainfall events. The main objectives of this study are to detect preferential movement of water in Chernozem soil and to employ numerical modeling to describe the variably saturated flow during a field ponded infiltration experiment. The infiltration experiment was performed at the Macov experimental station (Calcari-Haplic Chernozem in Danubian Lowland, Slovakia). The experiment involved single ring ponded infiltration. At the quasi steady state phase of the experiment dye tracer was added to the infiltrating water. Then the soil profile was excavated and the penetration pattern of the applied tracer was recorded. The abundance of biopores as a product of fauna and flora was found. To quantify the preferential flow effects during the infiltration experiment, three-dimensional axisymmetric simulations were carried out by a two-dimensional dual-continuum numerical model. The water flow simulations based on measured hydraulic characteristics without consideration of preferential flow effects failed to describe the infiltration experiment adequately. The 3D axisymmetric simulation based on dual-permeability approach provided relatively realistic space-time distribution of soil water pressure below the infiltration ring.

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Three-Dimensional Modelling of Non-Linear Wave-Induced Seabed Response around Offshore Open-Ended Pile

Journal of Marine Science and Engineering ◽

10.3390/jmse9111238 ◽

2021 ◽

Vol 9 (11) ◽

pp. 1238

Author(s):

Junwei Liu ◽

Shuiyue Chen ◽

Xin Li ◽

Zuodong Liang

Keyword(s):

Pore Water Pressure ◽

Soil Depth ◽

Water Pressure ◽

Three Dimensional ◽

Great Influence ◽

Parameter Analysis ◽

Degree Of Saturation ◽

Navier Stokes ◽

Linear Wave ◽

Wave Induced

This paper analyses the fluid–seabed–structure interactions (FSSI) around the open-ended pile by applying the in-house solver established on the open-source Computational Fluid Dynamics (CFD) platform. The Reynolds-averaged Navier–Stokes (RANS) equations are solved to simulate the hydrodynamic interactions between waves and open-ended piles. Biot’s poro-elastic theory (quasi-static model) is used to reproduce the wave-induced seabed responses. The parameter analysis indicates that the wave period, degree of saturation of seabed and pile diameter have a great influence on the development of the transient seabed liquefaction depth around the pile. In addition, the distribution of the pore water pressure vs soil depth in the inner zone of the pile presents a “V” shape rotated 90 degrees counterclockwise.

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Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.4.2020.05.0579 ◽

2020 ◽

Vol 14 (4) ◽

pp. 7369-7378

Author(s):

Ky-Quang Pham ◽

Xuan-Truong Le ◽

Cong-Truong Dinh

Keyword(s):

Stokes Equations ◽

Three Dimensional ◽

Axial Compressor ◽

Aerodynamic Performance ◽

Numerical Results ◽

Single Stage ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Operating Stability ◽

Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

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Experimental and Numerical Analysis of a Motorcycle Air Intake System Aerodynamics and Performance

International Journal of Automotive and Mechanical Engineering ◽

10.15282/ijame.17.1.2020.10.0565 ◽

2020 ◽

Vol 17 (1) ◽

Author(s):

M. A. Abd Halim ◽

N. A. R. Nik Mohd ◽

M. N. Mohd Nasir ◽

M. N. Dahalan

Keyword(s):

Combustion Process ◽

Three Dimensional ◽

Engine Performance ◽

Internal Flow ◽

Rapid Expansion ◽

Navier Stokes ◽

Turbulent Fluctuation ◽

Ansys Fluent ◽

Induction System ◽

Acceleration And Deceleration

Induction system or also known as the breathing system is a sub-component of the internal combustion system that supplies clean air for the combustion process. A good design of the induction system would be able to supply the air with adequate pressure, temperature and density for the combustion process to optimizing the engine performance. The induction system has an internal flow problem with a geometry that has rapid expansion or diverging and converging sections that may lead to sudden acceleration and deceleration of flow, flow separation and cause excessive turbulent fluctuation in the system. The aerodynamic performance of these induction systems influences the pressure drop effect and thus the engine performance. Therefore, in this work, the aerodynamics of motorcycle induction systems is to be investigated for a range of Cubic Feet per Minute (CFM). A three-dimensional simulation of the flow inside a generic 4-stroke motorcycle airbox were done using Reynolds-Averaged Navier Stokes (RANS) Computational Fluid Dynamics (CFD) solver in ANSYS Fluent version 11. The simulation results are validated by an experimental study performed using a flow bench. The study shows that the difference of the validation is 1.54% in average at the total pressure outlet. A potential improvement to the system have been observed and can be done to suit motorsports applications.

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