Fluid Mechanics for Chemical Engineering

First Name Last Name
Instructor
Hydraulics for civil engineering
7 April 2020
Hydraulics
Table of Contents
Task 1......................................................................................................................... 2
Task 1-part a).......................................................................................................... 2
Task 1-part b).......................................................................................................... 2
Task 1-part c).......................................................................................................... 2
Task 1-part d).......................................................................................................... 3
Task 1-part e).......................................................................................................... 3
Task 1-part f)........................................................................................................... 3
Task 1-part g).......................................................................................................... 4
Task 1-part h).......................................................................................................... 4
Task 2......................................................................................................................... 4
Task 2-part a).......................................................................................................... 4
Task 2-part b).......................................................................................................... 5
Task 2-part c).......................................................................................................... 5
Task 2-part d).......................................................................................................... 6
Task 3......................................................................................................................... 7
Task 3-part a).......................................................................................................... 7
Task 3-part b).......................................................................................................... 7
Task 3-part c).......................................................................................................... 8
Task 3-part d).......................................................................................................... 8
Task 4......................................................................................................................... 9
Task 4-part a).......................................................................................................... 9
Task 4-part b).......................................................................................................... 9
Task 4-part c)........................................................................................................ 10
References............................................................................................................... 11

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Task 1
Task 1-part a)
Pipe length =100m
Calculate pressure in the pipe: fluid pressure∈the pipe P=ρgH
P- pressure of fluid in the pipe,
g- gravitational acceleration
H- head of liquid column
Given reservoir height of 100 m , density of water as as 1000 kg
m3 ∧¿
gravitataional acceleration of 9.805 m/s 2.
pressure∈the pipe Pfluid=ρhg+ Pa(Falkovich , 2018)
Pfluid ∈the pipe=1000 kg /m3 x 100 mx 9.805 m/ s 2+101300 N /m 2=1.108 x 106 N /m2
Fluid pressure∈the open channel : Pfluid ∈open channel=ρhg=1000 kg/m3 x 1000mx 9.805 m/ s 2=9.81 x 105 N .
Task 1-part b)
Forces in a pipe:
i. intermolecular forces between layers. Friction between outer surface of fluid
and hence the edges of a conduit or pipe We know that particles have random
movements and often collide with one another. So, let's presume that certain
particles from top layer to the base layer and some from the bottom layer
move to the upper layer. This tension across surfaces contributes to significant
energy declines between surfaces at a fluid velocity.
ii. cohesive forces between molecules. The tension here between fluid surfaces
in the fluid itself. Cohesive forces can reasonably be described because as the
upper layer (suppose higher momentum) rises, the surrounding particles seek
to drag it up, reducing its momentum, and likewise the underside pushes the
surrounding particles ahead.
Task 1-part c)
The temperature change affects the viscosity of the fluid by changing the molecular
structure. As temperatures climb, the fluid warms up. It excites the particles and then
continue to move faster. The energy produced by the increase in temperature enables
the particles to migrate at a greater velocity to a point that they overcome the friction

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or friction effects of the particles. It decreases the viscosity of the substance by
allowing it more elastic (Fox, 2016).
Task 1-part d)
Laminar flow: The flow of the fluid, in which each particle of the fluid follows a
smooth course, pathways which never overlap with others. The effect of the laminar
flow is that the direction of a fluid appears constant at any stage in the stream. Even
so, in turbulent flow: irregular flow, characterized by tiny whirlpool areas. Clearly,
the velocity of this fluid is indeed not static at every moment (Landau & Lifshit︠s︡,
2012).
Task 1-part e)
The Reynolds number is the ratio of inertial forces to viscous forces. In action, the
Reynolds number is often used to determine whether the flow will be laminar or
turbulent. The dimensionless Reynolds number is determinant variable or indicative
in classifying a flow as either laminar or turbulent (Hibbeler, 2021). A flow in a pipe
is turbulent when the Reynolds number exceeds 4000.
Task 1-part f)
The boundary layer is a thin film of viscous fluid adjacent to the rigid portion of the
surface in connection with a flowing fluid whereby the velocity of flow ranges from
zero at the surface (in which the liquid "locks" at the wall due to its viscosity) to the
limit, which roughly correlates to the free flow velocity. (Kole, 2018) The crucial idea
of the boundary layer was recommended by L. Prandtl (1904), it characterizes the
boundary layer as a layer of liquid creating in streams with high Reynolds Numbers
Re, that is with generally high inertial forces as compared to the fluid’s viscosity.
This is seen when bodies are presented to high speed air stream or when bodies are
exceptionally big and the air stream speed is moderate.
Surface roughness triggers the change to turbulence in the boundary layer at all
Reynolds numbers, adding to early partition because of diminished drag and energy.
In shallow open channel streams, the surface impacts pervade through the greater part
of the boundary layer (Kariotoglou & Psillos, 2019). The completion of the mean
speed profiles, the wake parameter and the turbulence strength profiles rely upon the
scale of surface roughness and Reynolds number.