# Questions tagged [fluid]

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13 views

### Which colouring won't stain my AB Silicone

I made an aneurysm model out of AB silicone, which is pretty soft. I'm planning to do some fluid experiments with it by running water through the model. I want to use colored water (or maybe some kind ...
20 views

### Flow in vent of a pipe

I have a horizontal pipe of diameter 2000mm (uniform cross section), the pressure of gas flowing in the pipe is 1.2bar and the flow velocity is 15m/sec. there is a 100mm diameter vertical vent ...
55 views

### Pessure required for pumping seawater through pipe with inlet at a depth below sea level

I need to calculate the head capacity required at the pump, to pump sea water from a depth of 100m below sea level i.e. inlet is at 100m below sea level, the recieving end is at 5m above sea level. ...
39 views

### Can changing the topology of surface water initially hits change how much it splashes?

I am designing a crude funnel to feed into a portable dishwasher. I was not allowed to attach to water lines so I am stuck with pouring 1.5 large pitchers of water into it. I am designing a funnel to ...
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1 vote
39 views

### Why is electroosmotic flow plug-like?

Hey, I am studying for a microfluidic exam and can't wrap my head around electro osmotic flow: why is the velocity profile plug-like? The fluid motion in the bulk phase away from the double layer is ...
• 11
109 views

### Wind Load on conical structure

Is there a way to calculate the wind load acting on this conical cylinder? The wind pressure blowing through the hollow conical cylinder is at 30 bar. The conical cylinder is tilted at 10 degree ...
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23 views

### homework : torsors of constraints: Coulomb's laws

Bonjour , j’ai un devoir maison sur les torseurs mécaniques en lien avec la loi de Coulomb et Statiquecet je n’arrive pas à résoudre! Pouvez-vous m’aider s’il vous plaît?! Je met le sujet en photo ...
115 views

### Why does Surface Tension Result in a Meniscus in a Tube

In learning about fluid mechanics and surface tension, we learned that in particularly large pressure differences between two fluids and a relatively small diameter, we see either a concave or convex ...
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78 views

### CFD numerical methods (FEA, FVM, FDM,…)

I just read the answer from this question and have a question please: What I read: Computational Fluid Dynamics (CFD) refers to the use of the numerical techniques to solve fluid dynamical problems. ...
• 11
1 vote
134 views

### How can I stop water flow in a hose after a certain water level?

I have a bucket that I want to fill with water only up to a certain level, the bucket is indoors, the first thing I thought of was a siphon like the one in a toilet but would prefer a smaller ...
521 views

### How can I calculate the pressure in a pipe?

I am an engineering student designing a pipe system for a fluid flow and I calculated everything including the pressure loss. Now I have to choose a pipe material and pipe thickness for the piping ...
6 views

### What happens when electrolytic process rotameters are swapped for a much bigger one?

electrolytic process rotameter were swapped for much bigger rotameters. Inlet pipes are the still the same. What effect does the bigger rotameter have in the concentration of catholyte in the cell?
27 views

### How to achieve the choking condition at the orifice?

I have a geometry featuring two inlets. One inlet is designated for gaseous Ethylene, and the other is for gaseous Oxygen. During my computational analysis, I am unable to incorporate the complete ...
1 vote
126 views

### Effect of pipe size on water flow rate in municipal water system

am expanding my house and the town is requiring us to increase the size of the water line from the street from 3/4 inch to 1 inch diameter. intuitively i understand that a bigger pipe results in more ...
47 views

### Where in a fluidic fitting does the seal form?

Kind of a basic question but I'm confused on where the seal is formed in a fluidic fitting (diagram below, source: Idex). I know as the nut is screwed in, the end of the ferrule contacts the receiving ...
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17 views

### Split tubing assembly

I am designing a tubing (TPE) assembly that splits a single inlet line into either four or eight outlet lines. The goal is to achieve an approximately equal flow rate of mildly viscous liquid at each ...
158 views

### Optimal frequency for penetrating 1 meter of water using radio waves?

We are attempting to penetrate 1m of water featuring dissolved ions ( assume salinity of sea water) using radio waves. Aside for using wavelengths of very low frequency radio or below, what would be ...
40 views

### How can I anchor a rubber sheet that will be stretched?

I am designing a cylindrical container that will be filled with water. One end of the container will be solid with flow port and the other end will be a 3mm rubber sheet. I want to oscillate the ...
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274 views

### What is the theoretical explanation of flow work/energy?

Given the following definition of flow work: Reading and following the derivations I understand that in theory, this is only accurate when the fluid accelerates from rest. However, if we consider ...
• 57
89 views

### Pressure drop across orifice plate

I have been trying to estimate pressure loss caused by an orifice plate. The fluid flowing through it would be water. I found equations for discharge efficient and pressure loss coefficient K from ISO ...
1 vote
88 views

### Why do axial compressor stages have to get smaller and smaller to increase fluid pressure?

Why can't we design axial compressor stages of which have the same length? We are adding kinetic energy to fluid and then get it back as potential energy-static pressure. So why do we need that they ...
• 125
34 views

### What pressure do objects at exhaust of pipes feel from flowing fluid? Dynamic or Total?

Let's imagine that we have one fluid source separated somewhere in two pipes of R1 and R2, and we put one object at exhaust of R1 pipe and one more object at exhaust of R2 pipe (R1 > R2). Let's ...
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99 views

### Does a disk placed in a pipe perpendicular to flow direction of fluid feel dynamic pressure or total pressure?

There are two discs in the pipe but not at the same time. You can consider conditions with X but without Y, then with Y and without X. I am pretty sure that disc X will feel less force from fluid than ...
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452 views

### What would be the flow rate of 5 L hydrogen at 20 bar being vented through a 1/4 inch (assumed smooth) stainless steel pipeline to standard pressure?

As the title says, I have a 1 m pipe network of 1/4 inch diameter connected to a 5 L bottle of 20 bar hydrogen. If this system was to open suddenly, what would be the volumetric flow rate out the ...
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61 views

### Two Definitions of Kinematic Viscosity and it's Importance in Engine Oils

I have come across two definitions of kinematic viscosity and I am wondering about their relationship and significance in engine oils. One definition describes kinematic viscosity as momentum ...
• 395
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### where should center of gravity of cargo for the entire structure to be JUST stable?

My work: My answer for 1 is 2.5m (floats) For 2: MG must be positive and Ym - Yg must be positive I am not sure where to go from here.
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47 views

### Double Meniscus of Capillary Tube

I recently realized that if I turned my coffee cup downward, all the liquid spills out easily. This amazement prompted me to wonder about the impacts of surface tension for a situation in which the ...
49 views

### Are there compressors that can compress both water and water vapor?

I noticed while reading about compressors that they have various types and are generally made for a specific function. However, are there types of compressors (or pumps) that can compress both water ...
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28 views

### Optimal maintenance temperature and allowable drop for energy efficient hot water storage

I bought an under-sink electric boiler/hot water storage unit, for instant almost-boiling water. This device has an 'eco' mode, which broadens its hysteresis to 10 degrees C: it will allow the stored ...
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341 views

### Flow through Pipe annulus with pressure controlled opening

I have a pipe with radius $R_1$ with a smaller pipe within (radius $R_2$). I want to find an expression for the flow through the pipe which flows in the annulus area. However, the known values are the ...
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76 views

### Calculate height of water column to keep tank with fixed drain rate constantly filled?

I would like to know how to calculate the height of a water source connected with a 1/2 inch hose to a tank that is constantly draining @600L/H, such that the tank would never empty, i.e, the rate of ...
28 views

### Hydrostatic pressure on submerged surface

Can someone help me calculate the hydrostatic pressure on an immersed inclined body like the one in the figure? I know the force acting on the triangle is changing with height thus I can use an ...
76 views

### Water pump's output going down

So I have a submersible pump (Which I do not use submerged but just connect hose to both ends) who's output is consistently falling. While guessing for the causes I am tempted to blame one instance ...
53 views

### Movement caused by buoyancy

I have a rod that can rotate about a point, the rotation is caused by the buoyancy of 3 balls connected to the rod as in the picture: I need to calculate the angle at different heights and the ...
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1 vote
25 views

### Entropy in Euler equations for compressible flows

In compressible Euler equations, everyone knows the energy equation can be written as $$\dfrac{Ds}{Dt} =0$$ which implies the entropy is constant along the path line. However, we have shockwave as a ...
64 views

### Understanding continuity equation

The volume for an open tank is given: <$V = L \cdot L \cdot h(t)+ h(t)^2 \cdot tan(\theta)$> Where h is the volume of the liquid within the tank. I want to calculate the change in height as a ...
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58 views

### Submerged fraction buoancy force

How can I calculate the height of the submerged part of a partly filled bucket? (The liquid both inside and outside is freshwater). The bucket is trapezoidal such that the volume of the submerged can ...
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58 views

### Correct Hydraulic Symbol for Check Valve

I was looking in a few different hydraulic power textbooks for symbol information and I noticed that on of them referenced a check valve with this symbol: Is this "full" block symbol ever ...
56 views

### How does decreasing the cross-sectional width of a channel impact steady flow?

The continuity equation states that for a constant mass flow rate, if the cross sectional area of a channel is decreased, then velocity is increased. What happens if the channel has high walls and is ...
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1 vote
473 views

### Is supersonic flow not possible in a venturi tube?

I'm trying to design a venturi tube that will have a pressure drop of 91525 Pascals where the inlet pressure is at 1 atm and the throat pressure is at 9800 Pascals. I calculated the minimum throat ...
111 views

### Calculating the leakage of water in a pressurized vessel based on initial and final pressures?

Let's say you have a piping system containing liquid water under high pressure. One section of the pipe of ~70L gets isolated, and it is initially at the same pressure as when it was isolated, which ...
498 views

### Why do we need continuum approximation in fluid mechanics?

We know that a fluid in reality is not continuous. It has spaces and voids between atoms and molecules. Continuum approximation is a famous approximation that is taken in any fluid mechanics textbook. ...
110 views

### How to solve transient heat conduction equation at a point in space with volumetric heat source?

My system is a fluid exposed to light and I want to calculate the temperature change with time at a point, hence there are no spatial effects or convection due to the flow of the fluid. The heat ...
1 vote
1k views

### Airflow visible over the airplane wing

What's that visible airflow over the airplane wing and what causes it?
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35 views

### Consistent Fluid or powder flow through an orifice

This is a really odd and specific question, and I'm not sure this is even where to ask. A few weeks ago I thought about making a clock based on water flowing from an orifice. The obvious issue is that ...
33 views

### What is a good working fluid in the temperature range of 150 - 180 °F?

I am looking for a good working fluid whose boiling point is in the range of 150 - 180 °F for a waste heat recovery system. The fluid should be minimally flammable, preferably nontoxic, and low in ...
168 views

### Discharge at an angle in a channel concept question

Now I agree that the velocity of the discharge and the area is not at right angles, but I don't understand how using $\cos \theta$ helps? Shouldn't I use the area perpendicular to the channel? Like so:...
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148 views

### Difference between Front Tracking and Front Capturing Method

I am having difficulty understanding the difference between interface capturing and interface tracking schemes. It is important to track it for solving Navier Stokes equation and other fluid problems ...
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1 vote