Comparison of Driving Rain Index Calculated According to EN 15927-3 to the CFD Simulation and Experimental Measurement

2016 ◽  
Vol 861 ◽  
pp. 239-246 ◽  
Author(s):  
Peter Juras ◽  
Miroslav Jakubcik
Keyword(s):  
Experimental Measurement ◽  
Velocity Component ◽  
Cfd Simulation ◽  
Rain Gauge ◽  
Horizontal Velocity ◽  
Building Science ◽  
Moisture Source ◽  
Horizontal Velocity Component ◽  
Building Facades ◽  
Driving Rain

Wind-driven rain or driving rain is a rain which has given a horizontal velocity component by the wind. It can be the important moisture source for building façades and has been of the great concern in building science. In this article, the normative method described in STN EN ISO 15927-3:2009, was used for calculation of driving rain impact on vertical surfaces. This amount of rain was compared to the CFD simulation for selected location and to the experimental measurement carried out by wind-driven rain gauge.

scholarly journals Spray deposition within plant canopies

2000 ◽  
Vol 53 ◽  
pp. 248-252 ◽  
Author(s):  
B. Richardson ◽  
M. Newton
Keyword(s):  
Velocity Component ◽  
Spray Deposition ◽  
Horizontal Velocity ◽  
Pteridium Aquilinum ◽  
Fluorescent Tracer ◽  
Bracken Fern ◽  
Plant Canopies ◽  
Plane Normal ◽  
Horizontal Velocity Component ◽  
Arctostaphylos Patula

Spray deposition was measured within canopies of bracken fern (Pteridium aquilinum) and greenleaf manzanita (Arctostaphylos patula) following ground application of a spray mixture containing water a fluorescent tracer and surfactant A high proportion of spray (3538) reached the ground through manzanita canopies whereas only 113 reached the ground through a bracken canopy Spray deposition was closely linked to the quantity of foliage projected on a plane normal to the trajectory of droplets passing through the canopy Droplets that had trajectories with a significant horizontal velocity component were more effectively captured because of an increase in the quantity of foliage in their path

scholarly journals Wakes in stratified flow past a hot or cold two-dimensional body

1976 ◽  
Vol 75 (2) ◽  
pp. 233-256 ◽  
Author(s):  
G. E. Robertson ◽  
J. H. Seinfeld ◽  
L. G. Leal
Keyword(s):  
Velocity Component ◽  
Horizontal Velocity ◽  
Explicit Calculation ◽  
Two Dimensional ◽  
Line Heat Source ◽  
Oseen Flow ◽  
Horizontal Velocity Component ◽  
Self Similar ◽  
The Common ◽  
Jet Structure

This paper considers the general problem of laminar, steady, horizontal, Oseen flow at large distances upstream and downstream of a two-dimensional body which is represented as a line source of horizontal or vertical momentum, or as a line heat source or heat dipole. The fluid is assumed to be incompressible, diffusive, viscous and stably stratified. The analysis is focused on the general properties of the horizontal velocity component, as well as on explicit calculation of the horizontal velocity profiles and disturbance stream-function fields for varying degrees of stratification. For stable stratifications, the flow fields for all four types of singularities exhibit the common feature of multiple recirculating rotors of finite thicknesses, which leads to an alternating jet structure both upstream and downstream for the horizontal velocity component and to leewaves downstream in the overall flow. The self-similar formulae for the velocity, temperature and pressure at very large distances upstream and downstream are also derived and compared with the Oseen solutions.

scholarly journals Cavity Formation during Asymmetric Water Entry of Rigid Bodies

2021 ◽  
Vol 11 (5) ◽  
pp. 2029
Author(s):  
Riccardo Panciroli ◽  
Giangiacomo Minak
Keyword(s):  
Velocity Component ◽  
Water Entry ◽  
Rigid Bodies ◽  
Rigid Body Dynamics ◽  
The Body ◽  
Horizontal Velocity ◽  
Cavity Formation ◽  
Fluid Structure ◽  
Horizontal Velocity Component ◽  
The Stability

This work numerically evaluates the role of advancing velocity on the water entry of rigid wedges, highlighting its influence on the development of underpressure at the fluid–structure interface, which can eventually lead to fluid detachment or cavity formation, depending on the geometry. A coupled FEM–SPH numerical model is implemented within LS-DYNA, and three types of asymmetric impacts are treated: (I) symmetric wedges with horizontal velocity component, (II) asymmetric wedges with a pure vertical velocity component, and (III) asymmetric wedges with a horizontal velocity component. Particular attention is given to the evolution of the pressure at the fluid–structure interface and the onset of fluid detachment at the wedge tip and their effect on the rigid body dynamics. Results concerning the tilting moment generated during the water entry are presented, varying entry depth, asymmetry, and entry velocity. The presented results are important for the evaluation of the stability of the body during asymmetric slamming events.

Variability of the Horizontal Velocity Structure in the Upper 1600 m of the Water Column on the Equator at 10°W

2006 ◽  
Vol 36 (7) ◽  
pp. 1287-1304 ◽  
Author(s):  
Lucia Bunge ◽  
Christine Provost ◽  
Jonathan M. Lilly ◽  
Marc D’Orgeville ◽  
Annie Kartavtseff ◽  
...  
Keyword(s):  
Water Column ◽  
Velocity Component ◽  
Velocity Structure ◽  
Strong Dependence ◽  
Acoustic Doppler Current Profiler ◽  
Horizontal Velocity ◽  
Vertical Shear ◽  
Equatorial Atlantic ◽  
Entire Water Column ◽  
Current Profiler

Abstract This paper presents initial results from new velocity observations in the eastern part of the equatorial Atlantic Ocean from a moored current-meter array. During the “EQUALANT” program (1999–2000), a mooring array was deployed around the equator near 10°W that recorded one year of measurements at various depths. Horizontal velocities were obtained in the upper 60 m from an upward-looking acoustic Doppler current profiler (ADCP) and at 13 deeper levels from current meters between 745 and 1525 m. To analyze the quasiperiodic variability observed in these records, a wavelet-based technique was used. Quasiperiodic oscillations having periods between 5 and 100 days were separated into four bands: 5–10, 10–20, 20–40, and 40–100 days. The variability shows (i) a strong seasonality (the first half of the series is dominated by larger periods than the second one) and (ii) a strong dependence with depth (some oscillations are present in the entire water column while others are only present at certain depths). For the oscillations that are present in the entire water column the origin of the forcing can be traced to the surface, while for the others the question of their origin remains open. Phase shifts at different depths generate vertical shears in the horizontal velocity component with relatively short vertical scales. This is especially visible in long-duration events (>100 days) of the zonal velocity component. Comparison with a simultaneous lowered acoustic Doppler current profiler (LADCP) section suggests that some of these flows may be identified with equatorial deep jets. A striking feature is a strong vertical shear lasting about 7 months between 745 and 1000 m. These deep current-meter observations would then imply a few months of duration for the jets in this region.

scholarly journals Comparison of Mechanical Tests on the Dye-3, Greenland Ice Core and Artificial Laboratory Ice

1985 ◽  
Vol 6 ◽  
pp. 305 ◽  
Author(s):  
H. Shoji ◽  
C. C. Langway
Keyword(s):  
Ice Core ◽  
Ice Sheet ◽  
Main Property ◽  
Mechanical Tests ◽  
Horizontal Velocity ◽  
Axis Orientation ◽  
Horizontal Velocity Component ◽  
Temperature Levels ◽  
Property Changes ◽  
Physical And Chemical

The horizontal velocity of a thick ice sheet is maximum at the surface and decreases with increasing depth. The horizontal velocity profile at a given location differs from another location depending upon thein situstress and temperature conditions and the changing but distinctive physical and chemical character of the ice profile. The main property changes that influence the behavior of horizontal ice flow include chemical impurity concentration levels (both solid and dissolved components) and c-axis orientation. Shoji and Langway (1984) calculated the velocity profiles for both the Camp Century and Dye-3 Greeland location by taking into consideration possible enhancement factor variations over the profiles. This analysis was compared with the theoretical and experimental strain rate data obtained for laboratory ice at the same stress and temperature levels. This study indicated that the largest horizontal velocity component is the result of a highly enhanced shear deformation zone, a few hundred meters thick existing at the base of the ice sheet.

scholarly journals Numerical Simulation of the Performance Characteristics of the Hybrid Closed Circuit Cooling Tower

2008 ◽  
Vol 13 (1) ◽  
pp. 89-101 ◽  
Author(s):  
M. M. A. Sarker ◽  
E. Kim ◽  
G. C. Moon ◽  
J. I. Yoon
Keyword(s):  
Pressure Drop ◽  
Experimental Measurement ◽  
Cooling Tower ◽  
Cfd Simulation ◽  
Air Flow ◽  
Flow Distribution ◽  
Cooling Capacity ◽  
Performance Characteristics ◽  
Closed Circuit ◽  
Flow Rates

The performance characteristics of the Hybrid Closed Circuit Cooling Tower (HCCCT) have been investigated applying computational fluid dynamics (CFD). Widely reported CFD techniques are applied to simulate the air-water two phase flow inside the HCCCT. The pressure drop and the cooling capacity were investigated from several perspectives. Three different transverse pitches were tested and found that a pitch of 45 mm had lower pressure drop. The CFD simulation indicated that when air is supplied from the side wall of the HCCCT, the pressure drop can be over predicted and the cooling capacity can be under predicted mainly due to the non-uniform air flow distribution across the coil bank. The cooling capacity in wet mode have been calculated with respect to wet-bulb temperature (WBT) and cooling water to air mass flow rates for different spray water volume flow rates and the results were compared to the experimental measurement and found to conform well for the air supply from the bottom end. The differences of the cooling capacity and pressure drop in between the CFD simulation and experimental measurement in hybrid mode were less than 5 % and 7 % respectively for the uniform air flow distribution.

scholarly journals Optimization of Window Positions for Wind-Driven Natural Ventilation Performance

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2464
Author(s):  
Nari Yoon ◽  
Mary Ann Piette ◽  
Jung Min Han ◽  
Wentao Wu ◽  
Ali Malkawi
Keyword(s):  
Architectural Design ◽  
Natural Ventilation ◽  
Cfd Simulation ◽  
Design Decision ◽  
Building Facades ◽  
Window Position ◽  
Computational Fluid Dynamics Cfd ◽  
Ventilation Performance ◽  
Energy Simulations ◽  
The Impact

This paper optimizes opening positions on building facades to maximize the natural ventilation’s potential for ventilation and cooling purposes. The paper demonstrates how to apply computational fluid dynamics (CFD) simulation results to architectural design processes, and how the CFD-driven decisions impact ventilation and cooling: (1) background: A CFD helps predict the natural ventilation’s potential, the integration of CFD results into design decision-making has not been actively practiced; (2) methods: Pressure data on building facades were obtained from CFD simulations and mapped into the 3D modeling environment, which were then used to identify optimal positions of two openings of a zone. The effect of the selected opening positions was validated with building energy simulations; (3) results: The cross-comparison study of different window positions based on different geographical locations quantified the impact on natural ventilation effectiveness; and (4) conclusions: The optimized window position was shown to be effective, and some optimal solutions contradicted the typical cross-ventilation strategy.

Measurement and CFD Simulation of Wind-Driven Rain Using Eulerian Multiphase Model

2014 ◽  
Vol 1041 ◽  
pp. 265-268
Author(s):  
Peter Juráš
Keyword(s):  
Particle Tracking ◽  
Cfd Simulation ◽  
Rain Gauge ◽  
Multiphase Model ◽  
Simulation Tool ◽  
Rain Intensity ◽  
Free Standing ◽  
Particle Tracking Model ◽  
Tracking Model ◽  
Eulerian Multiphase Model

This paper deals with measurements of wind-driven rain intensity in Meteorological garden of Slovak hydrometeorological institute and subsequent modelling of free standing wind-driven rain gauge in OpenFoam CFD simulation tool using Eulerian multiphase model instead of common used Langrangian particle tracking model.

The problem of the flow of fluid to an imperfect drill hole

2019 ◽  
Vol 5 (3) ◽  
pp. 97-117
Author(s):  
Aleksandr I. Filippov ◽  
Oksana V. Akhmetova ◽  
Aleksei A. Kovalsky ◽  
Marat R. Gubaydullin
Keyword(s):  
Velocity Component ◽  
Transverse Velocity ◽  
Fluid Velocity ◽  
Single Layer ◽  
Maximum Modulus ◽  
Drill Hole ◽  
Darcy Law ◽  
Seepage Flows ◽  
Horizontal Velocity Component ◽  
Drill Holes

This article studies seepage flows arising from the selection of hydrocarbons from imperfect drill-holes. The authors observe the problem of pressure field in a homogeneous isolated isotropic homogeneous reservoir perforated in the range, completely contained in the layer of a common width.<br> To construct an analytical asymptotic solution, the single-layer initial problem is replaced by an equivalent three-layer symmetric, including the piezoconductivity equations for the perforated, covering, and underlying non-perforated layers, the initial and boundary conditions; on the conditional boundary of the perforated and non-perforated layers, the conditions of pressure and flow equality are specified (conjugation conditions). The solution of the problem is assumed to be regular&nbsp;— the value of the desired function, and, if necessary, its derivative at infinity is zero.<br> The problem is formulated in dimensionless quantities for the functions of the pressure deviation from its unperturbed distribution, normalized to the amplitude value of the depression. To solve the problem, the authors have developed an asymptotic method of a formal parameter. The solution of the problems for the zero and first coefficients of the asymptotic expansion is found in the space of the Laplace&nbsp;— Carson images in the variable <i>t</i>.<br> Based on the formulas obtained and the Darcy law, the authors construct graphical depen­dencies for the vertical and horizontal components of the fluid velocity filtered from the periphery to the well.<br> The computational experiment illustrates that there are no vertical flows at the exit to the well in the perforated part of the reservoir, and when removed from the well, these flows are different from zero, which indicates the presence of interlayer flows even in homogeneous imperfect drill holes. In the center of the perforated layer, such flows are absent, since the transverse velocity component vanishes. At the same time, the inflow in an imperfect drill hole is uneven, and the maximum modulus of the horizontal velocity component on all curves is reached at the boundary of the perforation interval.

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