scholarly journals Flow characteristics in a canine aneurysm model: A comparison of 4D accelerated phase-contrast MR measurements and computational fluid dynamics simulations

2011 ◽  
Vol 38 (11) ◽  
pp. 6300-6312 ◽  
Author(s):  
Jingfeng Jiang ◽  
Kevin Johnson ◽  
Kristian Valen-Sendstad ◽  
Kent-Andre Mardal ◽  
Oliver Wieben ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Phase Contrast ◽  
Flow Characteristics ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Aneurysm Model

Improving drowned drainage outlets with submerged orifices

2016 ◽  
Vol 11 (4) ◽  
pp. 849-856
Author(s):  
Evon E. W. Tang ◽  
Darrien Y. S. Mah ◽  
Onni Suhaiza Selaman
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Discharge Rate ◽  
Drainage System ◽  
Flow Characteristics ◽  
Computational Fluid Dynamics Simulations ◽  
Set Up ◽  
Dynamics Simulations ◽  
Submerged Orifice ◽  
Reduced Scale

Drowned outlets are common in riverine areas and sometimes unavoidable. Due to site restrictions, drainage discharge outlets are often submerged as the water level fluctuates during high tides or during the monsoon. As the runoff cannot be discharged through the outlet the drainage system fills up faster, leading to flash floods caused by overspill from the drains. This study is focused on the application of an on-site detention system with submerged orifice to improve the runoff delay from a drowned outlet. The application was investigated through a reduced-scale laboratory set up and then visualized with computational fluid dynamics simulations. The model was tested under different perpendicular flow velocities to analyze the workability and flow characteristics of the submerged orifice. The study showed that, with different headwater and tailwater levels, the energy level can be restored upstream of the orifice and ensure full flow of water from the submerged orifice even when hindered by perpendicular tailwater flow. Besides, the orifice jet's pattern changes with high velocity tailwater flow, although it does not slow down the discharge rate.

scholarly journals Aerodynamic analysis of uphill drafting in cycling

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
T. van Druenen ◽  
B. Blocken
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Scientific Literature ◽  
Sensitivity Analyses ◽  
Air Resistance ◽  
Wind Tunnel Measurements ◽  
Aerodynamic Effect ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

AbstractSome teams aiming for victory in a mountain stage in cycling take control in the uphill sections of the stage. While drafting, the team imposes a high speed at the front of the peloton defending their team leader from opponent’s attacks. Drafting is a well-known strategy on flat or descending sections and has been studied before in this context. However, there are no systematic and extensive studies in the scientific literature on the aerodynamic effect of uphill drafting. Some studies even suggested that for gradients above 7.2% the speeds drop to 17 km/h and the air resistance can be neglected. In this paper, uphill drafting is analyzed and quantified by means of drag reductions and power reductions obtained by computational fluid dynamics simulations validated with wind tunnel measurements. It is shown that even for gradients above 7.2%, drafting can yield substantial benefits. Drafting allows cyclists to save over 7% of power on a slope of 7.5% at a speed of 6 m/s. At a speed of 8 m/s, this reduction can exceed 16%. Sensitivity analyses indicate that significant power savings can be achieved, also with varying bicycle, cyclist, road and environmental characteristics.

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