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[′presh·ər ‚grād·ē·ənt]
(fluid mechanics)
The rate of decrease (that is, the gradient) of pressure in space at a fixed time; sometimes loosely used to denote simply the magnitude of the gradient of the pressure field. Also known as barometric gradient.
(meteorology)
The change in atmospheric pressure per unit horizontal distance, usually measured along a line perpendicular to the isobars.

the change in atmospheric pressure per unit of distance along a normal toward an equal pressure surface (isobaric front) in the direction of a decrease in pressure.

Horizontal pressure gradients are commonly used in meteorology—that is, horizontal components of pressure gradients established at sea level or at another level. In this case, the isobaric normal toward an isobar is taken at a given level. Normally a horizontal pressure gradient is 1–3 millibars per 100 km, but in tropical cyclones the gradient sometimes reaches tens of millibars per 100 km (1 millibar = 100 newtons per sq m). The concept of a barometric grade is often used instead of the vertical pressure gradient.

The change in pressure with horizontal distance at a fixed time. The higher the pressure gradient, the faster is the fluid flow.
References in periodicals archive ?
In this way, the relationship between permeability and pressure gradient can be obtained, as shown in Figure 2.
This can be clarified that an increase of the screw speed results in an increase of the theoretical chamber flow and the drag component of leakage flows, and finally it results in an increase of the pressure gradient since the flow rate remains constant.
For the single-layer coating bead Lee describes two expressions for the downstream pressure gradient (19):
This led to a decrease of the pressure gradient in the log and reduced the amount dye that permeated into it, resulting in reduced color change and dye uptake with longer vacuum time.
Any gas, regardless of its density, will develop an increased velocity gradient and an increased lateral wall pressure gradient as it flows through a partial obstruction.
When there is a leak, the pressure gradient changes and two linear segments appear with different slopes (orange).
From each processed array of sensor data, three scalar measures were calculated: (1) maximum pressure, (2) average pressure, and (3) RMS pressure gradient.
As a result of an extension of surface low pressure from the east , with the presence of high pressure on Saudi Arabia will cause a strong pressure gradient between the high and low pressure, that will accelerate the northwesterly winds from North Arabian Gulf," a statement by the NCMS said on Saturday.
As a result of an extension of surface low pressure from the east, with the presence of high pressure on Saudi Arabia, a strong pressure gradient between the high and low pressure has been created, which will accelerate the northwesterly winds from North Arabian Gulf," a statement from the NCMS said on Saturday.
The record-breaking conditions seem to happen when a wind pattern or an atmospheric pressure gradient tries to move the air back uphill, pushing against the air that was sliding down," Scambos explained.
1] investigated surface-tension-induced lung epithelial cell damage in a model of airway reopening, and they concluded that the steep pressure gradient near the bubble front was the most likely cause of the observed cellular damage.

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