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1500 questions
4
votes
1 answer
Why do parallel fans/blowers show an oscillatory behavior?
I am analyzing an industrial ventilation system that at some point operates two industrial size blowers in parallel. They often show oscillating behaviour: one blower briefly draws more power / generates more flow, and the other performs less. Then…
marqram
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4
votes
1 answer
Strongest brazing materials for titanium?
What are the strongest brazing materials for titanium?
The main materials I would like to use would be copper or silver, in which case I would like to ask which would form a stronger bond with titanium. Otherwise what are the strongest bond…
Tom
- 141
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4
votes
1 answer
Why is the point of failure load lower than the peak load?
In a tensile test the peak load was 69kN, but the point of failure load was 60kN. Why is it lower?
Harrison De George
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4
votes
2 answers
Interference fit problem in ANSYS Workbench 16.1 - how do I get rid of pressure/displacement raisers?
I have an interference fit problem of two perfect cylinders modelled in 2D using symmetry. The overall interface pressure is around 20MPa lower than the hand calculations and I get non-uniform displacement / pressure near the edges of the model. Any…
Josie Colclough
- 41
- 1
4
votes
0 answers
How should I set the turbulent prandtl number in a turbulent compressible flow simulation?
I'm working on simulating compressible fluid flow over a flat plate with turbulence. The energy equation for compressible flow with turbulence requires modeling a turbulent heat flux of the form
$$q_T=\frac{\mu_T c_p}{Pr_T}\frac{\partial…
Paul
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4
votes
1 answer
Is it normal to get different solutions with different ODE methods in MATLAB simulink?
I made a block diagram using simulink. When I solve it with ode45 and ode23 it gives me different graphs. Is it normal? Should I use the proper one?
m1=1.3608;
m2=0.096;
r=0.0592;
I2=0.0002175;
k1=186.3;
g=9.81;
Here is what the model looks…
Deccoyi
- 41
- 1
4
votes
4 answers
Selectively rotating (engaging/disengaging) one of 80 couplings on a small shaft?
I've been working on this problem for years (literally) and haven't yet found a workable, scalable, pragmatic, and cost-effective solution that would allow me to selectively rotate one or more of 80 discs closely aligned on a single, rotating shaft.…
Mahmoud Al-Qudsi
- 141
- 5
4
votes
1 answer
How can I check whether a nonlinear system is zero-state observable?
Given a nonlinear system, such as:
$$\begin{align}
x_1' &= x_2 \\
x_2' &= −x_1^3 + u \\
y &= x_2
\end{align}$$
How can I check the zero-state observability of the system?
Sardar_Usama
- 161
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4
votes
1 answer
Where exactly will a hydraulic jump occur?
I know that an hydraulic jump can occur only when the Froude number is higher than 1 (supercritical flow), and I am familiar with the Bélanger equation. However, I feel like I have a fundamental misunderstanding about hydraulic jumps: if a jump can…
user2554
- 215
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4
votes
1 answer
Determine the maximum possible yield strength for a single crystal of Fe pulled in tension
I am trying to solve the problem:
The critical resolved shear stress for iron is 27 MPa. Determine the
maximum possible yield strength for a single crystal of Fe pulled in
tension.
I think that this is related to the equation $\sigma_{yield} =…
strateeg32
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4
votes
3 answers
Calculating the minimum reflux ratio for separation of Acetone and Chloroform
Acetone must be recovered from a waste process stream, which also contains chloroform , so that it can be reused in the chemical process.
The chemical process requires however that before the recovered acetone can be reused in the process that…
Cian
- 41
- 2
4
votes
2 answers
AISC Section Modulus numbers
Why does the AISC handbook only list one figure for Section Modulus for shapes such as Angle(L) steel? Shouldn't there be two? The steel is asymmetric. Is the figure given just the Delta to the bottom or something; figuring a design only needs to…
Andyz Smith
- 222
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4
votes
1 answer
How to design a reinforced concrete ship keel?
I am building a small ship (or very large sailboat) that will have a concrete ballast at the base of the keel. I am looking to increase the weight of the concrete (lb/ft3), but I also want to maximize the impact resistance of the concrete to resist…
Escoce
- 141
- 3
4
votes
3 answers
How does a frequency to voltage converter work?
I am measuring the rotational speed of a shaft using a disk with 60 cuts and an optical fork. The signal from the optical fork is sent to a frequency to voltage converter and after that to a data acquisition system.
What is the working principle of…
Razvan
- 65
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4
votes
1 answer
Principal on gaining more height based on nested poles?
How do people design height gaining based on nested poles ?
Consider this picture (I made them) :
If I want to achieve height based on these 3 poles, how they should behave?
Is this how the behave?
I had been searching over the internet I haven't…
