scholarly journals Turbulent and Transitional Modeling of Drag on Oceanographic Measurement Devices

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
J. P. Abraham ◽  
J. M. Gorman ◽  
F. Reseghetti ◽  
E. M. Sparrow ◽  
W. J. Minkowycz
Keyword(s):  
Global Warming ◽  
Drag Coefficient ◽  
Computational Fluid Dynamic ◽  
Rate Equation ◽  
Fluid Dynamic ◽  
Heat Content ◽  
Fall Rate ◽  
Dynamic Techniques ◽  
Measurement Devices

Computational fluid dynamic techniques have been applied to the determination of drag on oceanographic devices (expendable bathythermographs). Such devices, which are used to monitor changes in ocean heat content, provide information that is dependent on their drag coefficient. Inaccuracies in drag calculations can impact the estimation of ocean heating associated with global warming. Traditionally, ocean-heating information was based on experimental correlations which related the depth of the device to the fall time. The relation of time-depth is provided by a fall-rate equation (FRE). It is known that FRE depths are reasonably accurate for ocean environments that match the experiments from which the correlations were developed. For other situations, use of the FRE may lead to depth errors that preclude XBTs as accurate oceanographic devices. Here, a CFD approach has been taken which provides drag coefficients that are used to predict depths independent of an FRE.

scholarly journals Numerical Investigation of the Flow around a Feather Shuttlecock with Rotation

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 28
Author(s):  
John Hart ◽  
Jonathan Potts
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Drag Coefficient ◽  
Numerical Investigation ◽  
Computational Fluid Dynamic ◽  
High Reynolds Number ◽  
Fluid Dynamic ◽  
Flow Structures ◽  
Drag Forces ◽  
High Reynolds

This paper presents the first scale resolving computational fluid dynamic (CFD) investigation of a geometrically realistic feather shuttlecock with rotation at a high Reynolds number. Rotation was found to reduce the drag coefficient of the shuttlecock. However, the drag coefficient is shown to be independent of the Reynolds number for both rotating and statically fixed shuttlecocks. Particular attention is given to the influence of rotation on the development of flow structures. Rotation is shown to have a clear influence on the formation of flow structures particularly from the feather vanes, and aft of the shuttlecock base. This further raises concerns regarding wind tunnel studies that use traditional experimental sting mounts; typically inserted into this aft region, they have potential to compromise both flow structure and resultant drag forces. As CFD does not necessitate use of a sting with proper application, it has great potential for a detailed study and analysis of shuttlecocks.

scholarly journals Computational fluid dynamic simulations for determination of ventricular workload in aortic arch obstructions

2013 ◽  
Vol 145 (2) ◽  
pp. 489-495.e1 ◽  
Author(s):  
Jessica S. Coogan ◽  
Frandics P. Chan ◽  
John F. LaDisa ◽  
Charles A. Taylor ◽  
Frank L. Hanley ◽  
...  
Keyword(s):  
Aortic Arch ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Dynamic Simulations

scholarly journals Body Shape Selection of "Bono Kampar" For Urban Concept Student Car Formula to Fulfill Indonesian Energy-Saving Standards (“KMHE”) with Aerodynamic Analysis

CFD letters ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 104-114
Author(s):  
Nazaruddin ◽  
Syafri ◽  
Yudi Saputra
Keyword(s):  
Drag Coefficient ◽  
Computational Fluid Dynamic ◽  
Body Shape ◽  
Energy Use ◽  
Energy Savings ◽  
Fluid Dynamic ◽  
Flow Simulation ◽  
The Body ◽  
Car Body ◽  
Selection Of

The body shape of a vehicle and the structure need to be considered when designing a vehicle. In addition, the shape of the body tends to significantly affect the vehicle's energy use to counter aerodynamic forces due to wind loads. Therefore, this research aims to determine the body length, width, height, wheel base and ground clearance of vehicles in the selection of Bono Kampar for Urban Concept Car Formula to Fulfill Indonesia Energy-Savings Standards (“KMHE”) with Aerodynamics Analysis. The methods used to create four models of vehicle bodies are dynamic simulation on Computational Fluid Dynamic software are coefficient drag, lift and bland force. The result showed that the car body design needs to have the smallest drag coefficient. This is because when vehicles have a large drag coefficient value, it tends to greatly influence its efficiency or performance. Furthermore, this is useful for minimizing fuel usage, and in allowing the vehicle to reduce the friction force caused by air while driving. The Computational Fluid Dynamic (CFD) software is used to obtain drag coefficients, which is used in Solid works Flow Simulation. From aerodynamic simulation results on four alternative car bodies carried out in this study, the smallest Cd (Coefficient Drag) is the second car body model, which has Drag Coefficient (Cd) of 0.21 Pa.

scholarly journals POLA ALIRAN FLUIDA PADA DELIQUIDISER

2018 ◽  
Vol 5 (2) ◽  
pp. 237-241
Author(s):  
Ragil T Indrawati
Keyword(s):  
Steady State ◽  
Drag Coefficient ◽  
Mass Flow ◽  
Computational Fluid Dynamic ◽  
Liquid Velocity ◽  
Fluid Dynamic ◽  
Solid Content ◽  
Working Pressure

ujuan penelitian ini untuk mengetahui fenomena pola aliran fluida yang terjadi pada deliquidiser serta properties yang ada pada daerah inlet, drain, oil outlet dan gas outlet. Penelitian dilakukan menggunakan pendekatan simulasi pemodelan matematis Computational Fluid Dynamic (CFD) menggunakan software Ansys. Dalam penelitian ini diasumsikan bahwa model akan disimulasikan skala 1:1 pada 2 phase fluida yaitu fase gas dan liquid dengan 2 jenis fluida (gas dan liquid). Simulasi akan mengacu pada kondisi steady state dan tidak ada solid content. Asumsi inlet fluid pada kondisi 5% turbulence, komposisi gas dan fraksi volume gas & liquid ialah konstan. Drag coefficient yang diguankan ialah 0.44 dengan working pressure 207 psi.Hasil penelitian menunjukkan bahwa bahwa persebaran fraksi gas dari bagian inlet tersebar secara merata pada semua bagian. Akan tetapi, setelah weirplate, ketika melewati nozzle dan menuju outlet gas, gas cenderung bergerak ke atas. Sedangkan, fraksi liquid mengalir dibagian bawah tengah ke bawah setelah fraksi gas. Gas dan liquid velocity streamline menunjukkan pola pergerakan dari inlet kemudian menumbuk weirplate, melewati nozzle dan keluar melalui outlet gas. Optimasi pada sistem telah dilakukan dan hasil yang diperoleh menunjukkan nilai fraksi gas dan fraksi liquid sebesar 0.74 dan 0.17 dalam aliran yang keluar dari bagian outlet. Sedangkan, untuk mass flow pada outlet gas sebesar 8.8 kg/s dan mass flow pada drain sebesar 0.05 kg/s.

scholarly journals ANALYSIS OF THE USE OF SPOILER ONE LEVEL AND TWO LEVELS IN CONDITIONS OF STEADY AGAINST THE DRAG AND LIFT COEFFICIENTS ON A SEDAN TYPE CAR BY USING CFD (COMPUTATIONAL FLUID DYNAMIC)

2019 ◽  
Vol 1 (2) ◽  
pp. 58
Author(s):  
Fajar Frihdianto ◽  
Nyeyep Sri Wardani ◽  
Indah Widiastuti
Keyword(s):  
Drag Coefficient ◽  
Steady Flow ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Lift Coefficient ◽  
Color Difference ◽  
Lower Surface ◽  
Significant Difference ◽  
The Difference ◽  
Drag And Lift

<p><em>This research was simulation analyzing the condition of steady flow in around of body car made and analized computly using CFD program (Computational Fluid Dynamic). The model used was Sedan car designed with different rear end body by adding spoiler. Analyzing in this research was done by using Software 18.2–CFD Student Version. Design of the three models were compared to find out the difference in magnitude of Coefficient of Drag, Coefficient of Lift, pressure distribution, velocity distribution, and behavioral character of flow around the rear end of car in the condition of steady flow. Model was made in appropriate scale with model of Honda city 2008 sedan car</em><em>. </em><em>Observation was made to look at the behavior of fluida flows both in front and back the car in different fluid speed ranges in steady condition.</em></p><p><em>The simulation results obtained from packet CFD on each condition were; model without spoiler, model with 1 level spoiler, and model with 2 level spoiler. Where this simulation showed that CD and CL were decrease</em><em>. </em><em>One of the example was at speed 40km/hour obtained the coefficient of drag (CD) of 0.31061, 0.28603, and 0.2054, it proved that 1 level spoiler could reduce the value of drag coefficient about 7.9135% of the sedan car without spoiler, while the car with 2 level spoiler could reduce the value of drag coefficient about 33.8592% without spoiler. For the coefficient of lift (CL) on each model was -0.38487, -0.54624, and -0.62097 proved that spoiler 1 level could reduce the value of lift coeffient about 41.92845% of the sedan car without spoiler, while the car with 2 level spoiler could reduce the value of lift coefficient about 61.35984% without spoiler. On the result of pressure distrubution and relative velocity give little affect to the upper and lower surface where this was indicated by almost no color difference contours. Then, if it was indicated from streamline and the formation of vortex, there was a significant difference so that it was very influential on the size of CD and CL occoured. By changing geometric proved that the spoiler car 1 and 2 level were more aerodynamic than the car without spoiler.</em></p>

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