# Relationship between velocity and pressure in si units

The SI unit for flow rate is . What is the relation between pressure, velocity of flow, and temperature of the fluid The SI unit is m3/s (cubic metres per second). pressure, and temperature. • The ideal gas law for dry air. – R d.: gas constant for dry air. • Equals to J/kg/K. – Note that P, ρ, and T have to be in S.I. units. The SI unit of viscosity is the pascal second [Pa s], which has no special name. (represented by the Greek letter ν "nu") is the ratio of the viscosity of a fluid to its density. As temperature increases, the average speed of the molecules in a liquid Viscosity is normally independent of pressure, but liquids under extreme .

Static Pressure Static pressure is felt when the fluid is at rest or when the measurement is taken when traveling along with the fluid flow. Since static pressure is what most pressure gauges measure, static pressure is usually what is implied when the term "pressure" is used in discussions.

Dynamic pressure is a function of the fluid velocity and its density and can be calculated from: Measuring Total, Static, and Dynamic Pressure.

### Volumetric flow rate - Wikipedia

When to Make the Distinction Depending on the application, the difference between total and static pressure may be negligible, but for others, neglecting the difference may result in costly mistakes. For many liquid applications, the pipelines are sized to ensure low fluid velocities to reduce the head loss and pressure drop for a given flow rate, resulting in a small value of dynamic pressure. In Figure 3, the pipe size is changed to result in different fluid velocities for gpm of water flow, resulting in different amounts of dynamic and static pressure for an inlet total pressure of psig.

For the low velocity case with a 6-inch pipe size, gpm results in a velocity of about 7.

Of the psig total pressure, If the pressure is measured on a psig pressure gauge, the difference between the total and static pressures will most likely not be discernible. In the moderate velocity case with a 4-inch pipe, gpm results in a fluid velocity of If you don't know the density of the liquid you can still determine the kinematic viscosity.

If you don't know the density of the sphere, but you know its mass and radius, well then you do know its density. Why are you talking to me? Go back several chapters and get yourself some education.

Should I write more? A newtonian fluid is one in which the viscosity is just a number.

A non-newtonian fluid is one in which the viscosity is a function of some mechanical variable like shear stress or time. Non-newtonian fluids that change over time are said to have a memory. Some gels and pastes behave like a fluid when worked or agitated and then settle into a nearly solid state when at rest.

## Volumetric flow rate

Such materials are examples of shear-thinning fluids. House paint is a shear-thinning fluid and it's a good thing, too. Brushing, rolling, or spraying are means of temporarily applying shear stress. This reduces the paint's viscosity to the point where it can now flow out of the applicator and onto the wall or ceiling.

Once this shear stress is removed the paint returns to its resting viscosity, which is so large that an appropriately thin layer behaves more like a solid than a liquid and the paint does not run or drip. Think about what it would be like to paint with water or honey for comparison. The former is always too runny and the latter is always too sticky.

Toothpaste is another example of a material whose viscosity decreases under stress.

Toothpaste behaves like a solid while it sits at rest inside the tube. It will not flow out spontaneously when the cap is removed, but it will flow out when you put the squeeze on it. Now it ceases to behave like a solid and starts to act like a thick liquid.