Contents
What is a recirculation region?
The recirculation region dimensions are characterised over a range of Reynolds numbers (1400–19000), with Reh based on the step height and the free stream velocity. Turbulent perturbations are produced in the free shear layer which develops between the recirculating flow close to the step and the free stream flow.
What is a wake region?
Wakes are narrow elongated regions aligned with the flow direction and filled with large and small eddies. The wake eddies of a bridge pier immersed in a river stream, or of a ship propelled through the water, are often visible on the surface.
Why is the wake a low pressure region?
Wake effects caused by viscosity The wake is the region of disturbed flow (often turbulent) downstream of a solid body moving through a fluid, caused by the flow of the fluid around the body. Parachutes deployed into wakes suffer dynamic pressure deficits which reduce their expected drag forces.
What is recirculation bubble?
The co-flowing jet, emitted with. lower velocity fluid at the nozzle exit where the. velocity of the surrounding fluid is relatively high, generates a recirculation bubble on the central. axis.
What causes recirculation?
The most common causes of access recirculation are the presence of high-grade venous stenosis, inadequate arterial blood flow rate, close proximity, or misdirection of arterial and venous needles placement by HD staff especially in new vascular accesses due to a lack of familiarity with the access anatomy.
What does recirculation mean?
: the act or process of circulating again or causing something to circulate again … which help convert the steam generated within the reactor back into water for recirculation in the closed loop system.—
Why is it called a wake?
The name “wake” originated because unknown diseases had plagued the countryside causing some to appear dead. As the family began to mourn, they would awaken. For this reason, the body is waked in the deceased’s home for at least one night.
Is the wake a low pressure region?
In fluid dynamics, a low pressure area on the downstream side of an object embedded in a flow. …
Is wake a low pressure region?
How do you check recirculation?
Access recirculation is diagnosed when the blood solute concentration in arterial line is lower than that of systemic circulation, indicating that there has been mixing of dialyzed blood with undialyzed blood entering the dialyzer.
What are four factors that can cause recirculation?
Factors that can affect the degree of recirculation include the pump speed, blood flow rates, direction of extracorporeal flow, and the cannula type, size, and position.
What’s the difference between a wake and a recirculation?
Generally the term ‘wake’ is used to describe any downstream disturbance to flow caused by an obstacle. Typically the wake will expand outwards in an approximate ‘V’ shape until it eventually dissipates into the general ‘noise’ of the flow whereas recirculation occurs is a reasonably well defined region immediately downstream of the obstacle.
Recirculation is a specific condition where the flow separates from the body of the obstacle. This creates a low pressure area immediately downstream which sucks fluid back into this region from the main flow with the net result of creating a circulating vortex or pair of vortices.
When is a recirculation zone likely to be encountered?
Recirculation Zone Recirculation zones are likely to be encountered at low flow rates that promote density stratification, and immediately prior to flow start-up, when slurry particles have been allowed to settle out. From: Managed Pressure Drilling, 2012
Where is the recirculation zone on a Reynolds cylinder?
For very small Reynolds numbers, the flow is completely laminar around the cylinder, with no recirculation and no instability. For larger Reynolds numbers, a recirculation zone appears behind the obstacle.