Aero and /or hydrodynamic properties are very important characters in hydraulic transport and handling as well as hydraulic sorting of agricultural products. To provide basic data for the development of equipment for sorting and sizing of agro commodities, several properties such as: physical characteristics and terminal velocity are needed. The two important aerodynamic characteristics of a body are its terminal velocity and aerodynamic drag. By defining the terminal velocity of different threshed materials, it is possible to determine and set the maximum possible air velocity in which material out of grain can be removed without loss of grain or the principle can be applied to classify grain into different size groups. In addition, agricultural materials and food products are routinely conveyed using air. For such operations, the interaction between the solid particles and the moving fluids determine the forces applied to the particles. The interaction is affected by the density, shape, and size of the particle along with the density, viscosity, and velocity of the fluid. This chapter discusses briefly with the different aerodynamic properties and their methods of measurement.

1. AERO DYNAMIC
PROPERTIES OF
FOOD
MATERIALS
Made by Ranit Sarkar

2. About Services Portfolio Team Contact
Ranit Sarkar
Need presentation
assistance?
https://www.linkedin.com/in/ranit-sarkar-
83b295209/
mailto:ranitsarkar71@gmail.com
https://t.me/Ranit_0_1
https://www.youtube.com/channel/UCirfpHbkvk
M9l4K4MVYh-Pw

3. INDEX
• INTRODUCTION
• FLUID
• DRAG FORCES
• DRAG COEFFICIENT
• TERMINAL VELOCITY
J

4. INTRODUCTION
Aero and /or hydrodynamic properties are very important characters in hydraulic transport
and handling as well as hydraulic sorting of agricultural products.
To provide basic data for the development of equipment for sorting and sizing of agro
commodities, several properties such as: physical characteristics and terminal velocity are
needed. The two important aerodynamic characteristics of a body are its terminal velocity
and aerodynamic drag.
By defining the terminal velocity of different threshed materials, it is possible to determine
and set the maximum possible air velocity in which material out of grain can be removed
without loss of grain or the principle can be applied to classify grain into different size
groups.
In addition, agricultural materials and food products are routinely conveyed using air. For
such operations, the interaction between the solid particles and the moving fluids determine
the forces applied to the particles.
J

5. FLUIDS
• A fluid is a substance which is amenable to
distortion when a force is applied upon it.
• Vapours, gases and liquids are classified as
fluids.
• They can flow through pipes, conduits and open
channels with the help of differential pressure.
• In foods hydrodynamics mainly deal with water
which is an incompressible fluid.
• Viscosity, pressure and density are the major
characteristics of liquids which influence its
dynamic properties.
J

6. DRAG FORCES
1. Opposes the motion of an object..
2. the drag force is proportional to some function of the velocity of
the object in that fluid.
3. depends upon the shape of the object, its size, its velocity, and
the fluid it is in.
4. Drag force (FD) is proportional to the square of the speed of the
object. We can write this relationship mathematically as
FD∝v2.
S

7. DRAG COEFFICIENT
The mathematical expression is given by,
Where ,
where C is the drag coefficient, A is the area of the object facing the fluid, and ρ is the density
of the fluid. This equation can also be written in a more generalized fashion as FD=bv2, where b is a constant
equivalent to 0.5CρA
S

8. TERMINAL VELOCITY
The terminal velocity of a particle may
be defined as equal to the air velocity
at which a particle remains in a
suspended state in a vertical pipe.
Drag
force
Weight
(mg)
R

9. FNET = ma =mg – ½ ρCAVt
2
0 =mg – ½ ρCAVt
2
R

10. TERMINAL VELOCITY PROPERTIES
1. Under the steady state conditions, after attaining the terminal velocity; if the density particle is
greater than the density of the fluid, the particle will move downward.
2. If the density of the particle is lesser than the density of the fluid, the particle will rise upward.
3. When air stream is used for separation of a product such as wheat from its associated foreign
materials such as straw and chaff, a knowledge of terminal velocity of all the particles involved
would define the range of air velocities affecting good separation of the grain from foreign
materials.
4. For these reasons, terminal velocity has been used as an important aerodynamic properties of
materials in such applications as pneumatic conveying and separation from foreign materials.
R
U

11. AIR CONVEYING
SYSTEM
APPILCATION
R
U

12. • work on the principle of fluidization,
• a material is converted from a static solid-like state to
a dynamic fluid-like state.
• hot gas or air is introduced through a perforated
distribution plate into the area holding the material.
This hot gas pumps through the spaces between solid
particles.
• As the velocity of the gas or air increases, the upward
forces on the particles increase, causing them to
equal the gravitational forces below.
• This creates a state of fluidization where the particles
are suspended in what appears to be a boiling bed of
liquid. What once moved in a solid way can now flow
like water.
• Each particle is in direct contact with, and surrounded
by, the hot gas or air – creating an efficient and
uniform drying process.
Fluid bed dryers
A

13. Separation of foreign
materials
A

14. J

15. About Services Portfolio Team Contact
Ranit Sarkar
Need presentation
assistance?
https://www.linkedin.com/in/ranit-sarkar-
83b295209/
mailto:ranitsarkar71@gmail.com
https://t.me/Ranit_0_1
https://www.youtube.com/channel/UCirfpHbkvk
M9l4K4MVYh-Pw

16. “
”
THANK YOU