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Kinematic viscosity

Kinematic viscosity

(OP)
Hi to everyone!
I have a doubt about the kinematic viscosity, the concept is: measure of the internal resistance of a body to flow under gravitational forces
if the temperature increases, the viscosity decreases and therefore the kinematic viscosity should be greater, since it is the time it takes for a fluid to travel through a capillary orifice under the force of gravity, if it is less dense, it should not offer less resistance and give high values ​​of kinematic viscosity, taking into account that the units are mm2/s.

RE: Kinematic viscosity

I'm not sure I totally understand the question you are asking.

Kinematic viscosity decreases with increasing temperature for most Newtonian fluids. Kinematic viscosity is a relationship between the dynamic viscosity and the density, so it isn't solely the density that causes this effect. Fluid properties related to shear stress play a huge part in viscometric properties.

- Andrew

RE: Kinematic viscosity

(OP)
Hi.
I understand that the viscosity decreases with increasing of the temperature because the distance between molecules of the fluid is higher but, the term kinematic means movement and if viscosity is lower the moviment is more. And the unit of measurement of kinematic viscosity is mm2/s,
If it increases temperature the fluid is able to travel more mm2/s.
Do you understand me now? That I want to mean.

RE: Kinematic viscosity

Don't get confused by the units, they are a mathematical artifice and don't really mean anything physical. The same is true for heat transfer coefficients. If you look at the defining equation for viscosity, there are meters of area, meters per second of velocity and meters of gap between two plates. These meters are not physically or logically related and therefore some are in the numerator and some are in the denominator. Then they are arbitrarily cancelled to simplify. It is like apples and oranges, they are not actually the same units. (meters of gap) is not related to (meters in a square). But the units do ultimately work out in the equation.

Kinematic viscosity is simply the ratio of two physical properties; viscosity and density. It is useful in engineering because two fluids with the same kinematic viscosity will flow though a tube under gravity forces at the same rate. More importantly the fluids will behave in the same way in a centrifugal pump.

RE: Kinematic viscosity

(OP)
Ah ok. I understand it, thanks!..to both!.
Have a good day.
Sometimes I analyses the things for the units, sometimes it's right but other times that don't define anything.
Sorry for my english, jjj..
Bye!

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