scholarly journals CFD Analysis of Flow Over Pickup Truck with And Without Covering Cargo Area Using OpenFOAM

2021 ◽  
Vol 90 (1) ◽  
pp. 40-51
Author(s):  
Abed Alrzaq Alshqirate ◽  
Dastan Zrar Ghafoor ◽  
Sachin L. Borse
Keyword(s):  
Saudi Arabia ◽  
Drag Coefficient ◽  
Lift Force ◽  
Recirculation Zone ◽  
Full Scale ◽  
Cfd Analysis ◽  
Pickup Truck ◽  
Speed Range ◽  
Inclined Surface ◽  
Surface Covering

Pickup truck serves purpose as car as well as small truck. Pickup truck is popularly used in USA and Saudi Arabia. Pickup truck consists of enclosed cab and an open cargo space. Here CFD analysis of full scale pickup truck is performed using free CFD software OpenFOAM for speed range from 40km/hr to 140km/hr. For turbulence modelling k-ω model is used. This work investigates effect of covering cargo area on aerodynamics drag. Covering cargo area decreases drag coefficient by 5.2% by horizontally covering cargo area whereas decreases by 13% by inclined surface covering cargo area. Thus, covering cargo area reduces drag coefficient as recirculation zone is reduced. Inclined cover case shows drastic rise in lift force, requiring attention for safety as traction will be affected.

Preliminary Evaluation of the 24 Ft. Diameter Fan Performance In the MinWaterCSP Large Cooling Systems Test Facility

2021 ◽  
Author(s):  
S. J. van der Spuy ◽  
D. N. J. Els ◽  
L. Tieghi ◽  
G. Delibra ◽  
A. Corsini ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Static Pressure ◽  
Cooling System ◽  
Pressure Rise ◽  
Full Scale ◽  
Test Facility ◽  
Small Scale ◽  
Preliminary Evaluation ◽  
Cfd Analysis ◽  
Setting Angle

Abstract The MinWaterCSP project was defined with the aim of reducing the cooling system water consumption and auxiliary power consumption of concentrating solar power (CSP) plants. A full-scale, 24 ft (7.315 m) diameter model of the M-fan was subsequently installed in the Min WaterCSP cooling system test facility, located at Stellenbosch University. The test facility was equipped with an in-line torque arm and speed transducer to measure the power transferred to the fan rotor, as well as a set of rotating vane anemometers upstream of the fan rotor to measure the air volume flow rate passing through the fan. The measured results were compared to those obtained on the 1.542 m diameter ISO 5801 test facility using the fan scaling laws. The comparison showed that the fan power values correlated within +/− 7% to those of the small-scale fan, but at a 1° higher blade setting angle for the full-scale fan. To correlate the expected fan static pressure rise, a CFD analysis of the 24 ft (7.315 m) diameter fan installation was performed. The predicted fan static pressure rise values from the CFD analysis were compared to those measured on the 1.542 m ISO test facility, for the same fan. The simulation made use of an actuator disc model to represent the effect of the fan. The results showed that the predicted results for fan static pressure rise of the installed 24 ft (7.315 m) diameter fan correlated closely (smaller than 1% difference) to those of the 1.542 m diameter fan at its design flowrate but, once again, at approximately 1° higher blade setting angle.

A new moving model test method for the measurement of aerodynamic drag coefficient of high-speed trains based on machine vision

2017 ◽  
Vol 232 (5) ◽  
pp. 1425-1436 ◽  
Author(s):  
Zhiwei Li ◽  
Mingzhi Yang ◽  
Sha Huang ◽  
Dan Zhou
Keyword(s):  
Machine Vision ◽  
Drag Coefficient ◽  
Model Test ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Full Scale ◽  
Test Method ◽  
Test Accuracy ◽  
Friction Resistance ◽  
Aerodynamic Drag Coefficient

A moving model test method has been proposed to measure the aerodynamic drag coefficient of a high-speed train based on machine vision technology. The total resistance can be expressed as the track friction resistance and the aerodynamic drag according to Davis equation. Cameras are set on one side of the track to capture the pictures of the train, from which the line marks on the side surface of the train are extracted and analyzed to calculate the speed and acceleration of the train. According to Newton’s second law, the aerodynamic drag coefficient can be resolved through multiple tests at different train speeds. Comparisons are carried out with the full-scale coasting test, wind tunnel test, and numerical simulation; good agreement is obtained between the moving model test and the full-scale field coasting test with difference within 1.51%, which verifies that the method proposed in this paper is feasible and reliable. This method can accurately simulate the relative movement between the train, air, and ground. The non-contact measurement characteristic will increase the test accuracy, providing a new experimental method for the aerodynamic measurement.

Large Eddy Simulations of Flow Past Two Pipelines in Tandem in Close Proximity to the Seabed

2017 ◽  
Author(s):  
Zhong Li ◽  
Mia Abrahamsen Prsic ◽  
Muk Chen Ong ◽  
Boo Cheong Khoo
Keyword(s):  
Drag Coefficient ◽  
Recirculation Zone ◽  
Separation Distance ◽  
Large Eddy Simulations ◽  
Plane Wall ◽  
Scale Model ◽  
Tandem Cylinders ◽  
Flow Past ◽  
Large Eddy ◽  
The Mean

Three-dimensional Large Eddy Simulations (LES) with Smagorinsky subgrid scale model have been performed for the flow past two free-spanning marine pipelines in tandem placed in the vicinity of a plane wall at a very small gap ratio, namely G/D = 0.1, 0.3 and 0.5. The ratio of cylinder center-to-center distance to cylinder diameter, or pitch ratio, L/D, considered in the simulations is taken as L/D = 2 and 5. This work serves as an extension of Abrahamsen Prsic et al. (2015) [1]. In essence, six sets of simulations have been performed in the subcritical Reynolds number regime at Re = 1.31 × 104. Our major findings can be summarized as follows. (1) At both pitch ratios, the wall proximity has a decreasing effect on the mean drag coefficient of the upstream cylinder. At L/D = 2, the mean drag coefficient of the downstream cylinder is negative since it is located within the drag inversion separation distance. (2) At L/D = 2, a squarish cavity-like flow exists between the tandem cylinders and flow circulates within the cavity. A long lee-wake recirculation zone is found behind the downstream cylinder at G/D = 0.1. However, a much smaller lee-wake recirculation zone is noticed at L/D = 5 with G/D = 0.1. (3) At L/D = 2, the reattachment is biased to the bottom shear layer due towards the deflection from the plane wall, which leads to the formation of the slanted squarish cavity-like flow where the flow circulates between the tandem cylinders.

Analysis of lift and drag coefficients of a GT2 racing car at various speeds with movable wheels and ground

2015 ◽  
Vol 12 (3) ◽  
pp. 261-270
Author(s):  
Albert Boretti
Keyword(s):  
Wind Tunnel ◽  
Drag Force ◽  
Computational Fluid Dynamic ◽  
Lift Force ◽  
Fluid Dynamic ◽  
Time Simulation ◽  
Rear Wing ◽  
Speed Range ◽  
Drag And Lift ◽  
Lift And Drag

The paper proposes a study of a GT2 racing car with a computational fluid dynamic (CFD) tool. Results of STAR-CCM+ simulations of the flow around the car in a wind tunnel with movable ground and wheels are presented for different air speeds to assess the different contributions of pressure and shear to lift and drag over the speed range. The rear wing contributes more than 85% of the lift force and 7-8% of the drag force for this particular class of racing cars. When reference is made to the low speed drag and lift coefficients, increasing the speed from 25 to 100 m/s produces an increase of CD of more than 3% and a reduction of CL of more than 2%. The resultsuggests modifying the constant CD and CL values used in lap time simulation toolsintroducing the tabulated values to interpolate vs. the speed of the car.

scholarly journals CFD Analysis of Flow Fields under Bow Bottom of Ships in Full-Scale

2016 ◽  
Vol 24 (0) ◽  
pp. 31-38
Author(s):  
Takanori Hino ◽  
Hideyuki Ando ◽  
Masahiko Tanigawa ◽  
Yasuhiro Sudo ◽  
Koji Sugita ◽  
...  
Keyword(s):  
Flow Fields ◽  
Full Scale ◽  
Cfd Analysis

Modeling Strategy and Numerical Validation for a Darrieus Vertical Axis Micro-Wind Turbine

2010 ◽  
Author(s):  
Marco Raciti Castelli ◽  
Guido Ardizzon ◽  
Lorenzo Battisti ◽  
Ernesto Benini ◽  
Giorgio Pavesi
Keyword(s):  
Wind Turbine ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Cfd Analysis ◽  
Mesh Quality ◽  
Induced Drag ◽  
Node Distribution ◽  
Spatial Grid ◽  
Modeling Strategy

This paper presents a model for the evaluation of optimal spatial grid node distribution in the CFD analysis of a Darrieus vertical axis micro wind turbine, by analyzing the trends over a 360° rotation of some indicators of near-blade mesh quality. To this purpose, a complete validation campaign has been conducted through a systematic comparison of numerical simulations with wind tunnel experimental data. Both two-dimensional and three-dimensional grids, characterized by average y+ values of 30 and 1, have been tested by applying some statistical techniques as a guidance in selecting the appropriate grid configuration and corresponding turbulence model. Finally, the tip downstream recirculation zone due to the finite blade extension and the influence of spokes have been analyzed, achieving a numerical quantification of the influence of induced drag and spokes drag on overall rotor performance.

Resistance Prediction on Submerged Axisymmetric Bodies Fitted with Turbulent Spot Inducers

2015 ◽  
Vol 59 (02) ◽  
pp. 85-98
Author(s):  
Young T. Shen ◽  
Michael J. Hughes ◽  
Joseph J. Gorski
Keyword(s):  
Drag Coefficient ◽  
Form Factors ◽  
Model Tests ◽  
Full Scale ◽  
Turbulent Spot ◽  
Friction Drag ◽  
Noticeable Effect ◽  
New Device ◽  
Model Scale ◽  
Marine Industry

A method to predict bare hull ship resistance is presented in this article. Hull resistance is assumed to consist of friction drag and residual drag. The friction drag coefficient is represented by an equivalent flat plate coefficient multiplied by a form factor to incorporate effects of body geometry and boundary layer (BL) characteristics on drag. Theories of form factors including the effect of BL transition locations have been successfully derived. Form factors are shown to have a noticeable effect on body drag at high Reynolds numbers (Re) and a significant effect at model Re. Residual drag coefficient is obtained from model tests with application of scaling formulae to relate model scale residual drag coefficient to full scale drag coefficient. To address the issue of laminar flow on models in residual drag measurements, a new device termed a "turbulent spot inducer" is introduced in model tests. Finally, a new scaling formula to relate model scale residual drag coefficient to full scale residual drag coefficient with the flow on body surface partly laminar and partly turbulent is derived. It is shown that a traditional 1þK scaling method used in the marine industry is a special case of the newly derived residual drag scaling formula.

New Insights into Voith Schneider Tractor Tug Capability

1993 ◽  
Vol 30 (04) ◽  
pp. 233-242
Author(s):  
Bruce L. Hutchison ◽  
David L. Gray ◽  
Sridhar Jagannathan
Keyword(s):  
Computer Simulations ◽  
Model Tests ◽  
Full Scale ◽  
Speed Range

The emerging use of tanker escort in restricted waters requires tugs that are capable of rendering effective retarding and steering assistance to large ships operating in the 6 to 12 knot speed range. This paper presents findings from a coordinated program of model tests, computer simulations and full scale trials which have yielded new insights into the capabilities of Voith Schneider propelled tractor tugs. The emergency assist capabilities are shown as speed-dependent contours of the vector assist force in the coordinates of the assisted vessel. For tractor tugs the capabilities increase with speed. Simulations of tug assisted tanker maneuvers at 10 knots show that the tractor tug is more effective than a conventional tug in controlling the behavior of a disabled tanker.

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