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# Dynamic Vs Kinematic Viscosity (Difference & Definition)

## What is Dynamic Viscosity?

• Rate of shear stress is directly proportional to the velocity gradient
• Dynamic viscosity is flowed the newton 2nd Law (Second law) as per newton second law of motion. He says which relates the acceleration with the forces.
• Due to the force exerted on the material, the deformation causes the fluid-fluid particle to move.
• Science ‘fluid’ Kinematics viscosity, studying only motion without thinking of force.
• This chapter presents the first primary discussion of the science of fluid force fluid dynamics and its practical and general application.
• A clear concept of force and acceleration is necessary to understand the speed of the transmission.
According to Newton’s law of motion (Newton’s Second Law of Motion),
• force (force) = Mass X Acceleration
• f = m.a  (F=Force, M= Mass, A = Acceleration)
• It is usually the practice of using m (Mass) in the pursuit of force for a solid.
• But the Greek letter p is used for fluid-fluid particulars.
• Acceleration is used only for acceleration or for acceleration.
• The actual force applied to a particular solution according to Newton’s rule – net force,
Its product of force and acceleration is equal to – product.
•  Thus the fluid has viscosity – viscosity. But to develop equations of motion, the equation is considered inviscid – inviscid.
• In reality, no true view is devoid of real fluid. But other factors such as pressure force – pressure force and gravity force –
Since the viscous effect is insignificant relative to the gravitational force, it can be ignored, and in doing so, there is no possibility of major impairment.
• One fact should be noted that in some cases, the force of prudence may also be important.
• For example, glycerin cannot be ignored when a fluid flows into a narrow tube or flows between two adjacent surfaces.
•  Since airtightness is extremely low in air motion, it can be easily ignored, but the fact that air is compressible cannot be ignored.
• Assuming that the pressure of convection is caused by gravitational force, the equation can be written as follows (Dynamic Vs Kinematic Viscosity).
• Actual tension force on gravity + gravitational force = volume of force x its acceleration Net pressure force on a fluid particle + net gravity force on a fluid particle = particle mass x particle acceleration.

### τ = µ x du/dy

• du/dy = constant of proportionality
• µ = Dynamic viscosity
• τ = Coefficient Euler’s equation of motio

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### Equation of motion

#### (1/p) x (dp/ds) = -v x (dv/ds)

• p = Density of fluid
• dA = Cross-sectional area of the fluid element
• ds = Length of the fluid element
• dW = Weight of the fluid element
• P = Pressure on the element at A
• P+dP = Pressure on the element at B
• v = velocity of the fluid element

### P+(1/2).p.v.v +p.g.h = Constant

• P = Pressure on the element at A
• p = Density of fluid
• v = Velosity
• h = elvation
• g = gravitational elevation

## What is Kinematic Viscosity?

• Kinematic viscosity: Defined as the ratio of dynamic viscosity (mass viscosity) of a fluid
• Mathematically,

### Kinematic viscosity  ∝ = Dynamic viscosity (µ) / Density (δ)

• ∝ = Kinematic viscosity
• µ = Dynamic viscosity
• δ = Density

### ∝ = µ / δ

• Topics related to acceleration and types of motion, etc. are discussed.
• An initial discussion of the equation for pressure and total force and pressure center due to the viscosity properties and the static mass.
• It also moves due to a very small amount of learner stress on the visual.
• Likewise, the motion is also due to the slight imbalance in the membrane pressure on the visual.

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### Type of Kinematic Viscosity flow-

2. Uniform and non-uniform flows
3. Laminar and turbulent flows
4. Compressible and incompressible flows
5. Rotational and irrotational flows
6. One, two, and three-dimensional flows

• Steady flow: the type of flow in which the fluid properties Remains constant with time.

### u,v,w=0  dv/dt=0 dv/ds =0

• dv= change of velocity
• dt = time
• ds = length of flow in the direction S
• Unsteady flow: type of flow in which the fluid properties changes with time.

### dv/dt ≠ 0  dv/ds =0

• dv= change of velocity
• dt = time
• ds = length of flow in the direction S

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### 2. Uniform and non-uniform flows:-

• Uniform flows: A type of flow in which velocity pressures, density, temperature, etc. At only give time does not change with respects to scope.

### dv/ds = 0, dp/ds = 0

• dv = change of velocity
• dt = time
• ds = length of flow in the direction S

• Non-Uniform: velocity, pressures, density, etc. at give time change with respect to space

### dv/ds ≠ 0, dp/ds =0

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### 3. Laminar and turbulent flows

• Laminar flow: Defined as that type of flow in which the fluid particles move along well-defined paths or streamline, and all the streamline is strength and parallel.
• Laminar flow is also called viscous flow or stream,
• This type of flow is only possible at slow speed and in a viscous fluid

• Turbulent flow: in which fluid particles more irregularly and disorderly, i.e., fluid particles move in a zig-zag way. The zig-zag irregularly of fluid properties is responsible for high energy loss.

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### 4. Compressible and Incompressible Flows.

• Compressible flow: Type of flow in which the density of the fluid changes from point to point or in other words, the density (p) is not constant for the fluid.
• Thus, mathematically, for compressible flow

### p  ≠ Constant

• Incompressible flow: Type of flow in which the density is constant fluid flow. Liquids are generally incompressible then gases are compressible.
• Mathematically, for incompressible flow

### p = Constant.

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### 5. Rotational and Irrotational Flows.

• Rotational flow: that type of flow in which the fluid particles, while flowing along stream-lines, also rotate about their own axis.
• Irrotational Flows: Fluid particles while flowing along stream-lines, not rotate about their own axis then that type of flow is called irrotational flow.

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### 6. One, Two, and Three-Dimensional Flow.

• One-dimensional:
• This is the flow in which the flow parameter such as velocity is a function of time, and one space co-ordinates only, say axis X.
• For a steady one dimensional flow in direction, the velocity is a function of one-space and co-ordinate only.
• The variation of velocities in other two mutually perpendicular directions is assumed negligible.
• Hence mathematically, for one-dimensional

### flow u =f( x), v = 0 and w = 0

• Where u, v and w are velocity components in x, y and z directions respectively.
• Two-dimensional flow:
• Tthat type of flow in which the velocity is a function of time and two rectangular space co-ordinates say x and y.
• For a steady two-dimensional flow, the velocity is a function of two space coordinates only.
• The variation of velocity in the third direction is negligible.
• Thus, mathematically for two-dimensional flow

### u = fi(x, y), v = f2(x, y) and w = 0.

• Three-dimensional flow:
• That type of flow in which the velocity is a function of time and three mutually perpendicular directions.
• But for a steady three-dimensional flow, the fluid parameters are functions of three space coordinates (x, y, and z) only.
• Thus, mathematically, for three-dimensional flow