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Search: Posts Made By: TurbJet
Forum: Main CFD Forum January 4, 2021, 15:11
Replies: 16
Views: 364
Posted By TurbJet
When you mention "flux with dissipation" in...

When you mention "flux with dissipation" in density-based solver, are flux-limiter/slope-limiter one of them?

Anyway, really appreciate it! It's really helpful!
Forum: Main CFD Forum January 3, 2021, 18:25
Replies: 16
Views: 364
Posted By TurbJet
Yes, that is exactly my confusion: the book is...

Yes, that is exactly my confusion: the book is very different from those discussing density-based solver, at least at the level I can understand.

Could you briefly introduce some of the numerical...
Forum: Main CFD Forum January 3, 2021, 15:05
Replies: 16
Views: 364
Posted By TurbJet
So can I say that all the methods in, e.g.,...

So can I say that all the methods in, e.g., approximate Riemann solvers or methods like flux splitting, can be extended to incompressible flow? In Ferziger's book, I don't think they ever mention the...
Forum: Main CFD Forum January 3, 2021, 15:01
Replies: 16
Views: 364
Posted By TurbJet
Maybe it just me, but I think Versteeg's book is...

Maybe it just me, but I think Versteeg's book is awfully like Ferziger's, especially the notations.
Forum: Main CFD Forum January 3, 2021, 14:22
Replies: 16
Views: 364
Posted By TurbJet
I see your point. But based on Ferziger's...

I see your point.

But based on Ferziger's book, seems like they never mention anything about this two-states situation. Also, they didn't introduce any numerical fluxes (if I am not missing...
Forum: Main CFD Forum January 3, 2021, 00:10
Replies: 16
Views: 364
Posted By TurbJet
Finite volume method for incompressible & compressible flow

Greetings,

In Ferziger's book, for FVM, no matter what kind of interpolation scheme they discuss (in Chap.4.4, e.g., CDS, UDS, QUICK, etc), the values on cell faces are unique (if I understand it...
Forum: Main CFD Forum December 13, 2020, 20:41
Replies: 2
Views: 125
Posted By TurbJet
Basic tensor algebra

Greetings,

I am confused by the following tensor operation:

1. tensor contraction
\pmb{A}:\pmb{A} = A_{ij}A_{ji}

2. tensor norm
|\pmb{A}| = (2A_{ij}A_{ij})^{1/2}
Forum: Main CFD Forum June 14, 2020, 03:48
Replies: 16
Views: 369
Posted By TurbJet
Is this figure in log-log plot, linear-linear...

Is this figure in log-log plot, linear-linear plot, or linear-log plot?
Forum: Main CFD Forum June 14, 2020, 03:39
Replies: 2
Views: 309
Posted By TurbJet
Approximate Riemann solver and reconstruction

Greetings,

(Approximate) Riemann solvers are originally designed for piecewise-constant states on both sides, which can be considered as "piecewise-constant" reconstruction when it comes to...
Forum: Main CFD Forum May 13, 2020, 19:08
Replies: 13
Views: 556
Posted By TurbJet
I see. Great explanation and thanks a lot!

I see. Great explanation and thanks a lot!
Forum: Main CFD Forum May 13, 2020, 16:37
Replies: 13
Views: 556
Posted By TurbJet
Could you explain more on this specific case that...

Could you explain more on this specific case that you gave? Why this spreading peak would affect the accuracy? Is it because it can't be accurately represented on a uniform grid?
Forum: Main CFD Forum May 13, 2020, 16:29
Replies: 13
Views: 556
Posted By TurbJet
Thanks for your previous reply. So I'll probably...

Thanks for your previous reply. So I'll probably try both approaches.
Forum: Main CFD Forum May 12, 2020, 22:49
Replies: 13
Views: 556
Posted By TurbJet
I did some digging after I posted this thread,...

I did some digging after I posted this thread, most of the contents are applied to CFD (at least from what I can tell). However, I am looking for a general approach that can be simply applied to...
Forum: Main CFD Forum May 12, 2020, 22:42
Replies: 13
Views: 556
Posted By TurbJet
Is this applicable to 1D case? I am just looking...

Is this applicable to 1D case? I am just looking for an approach to differentiate a function on a non-uniform grid. The paper I referred to use this least-squares approximation to find out the...
Forum: Main CFD Forum May 12, 2020, 22:37
Replies: 13
Views: 556
Posted By TurbJet
Maybe, but I am not sure. The paper I read is...

Maybe, but I am not sure. The paper I read is using this least-squares approximation to approximate the 2nd-order derivative of the energy flux of HIT in spectral space. The reason they're using this...
Forum: Main CFD Forum May 12, 2020, 01:05
Replies: 13
Views: 556
Posted By TurbJet
Least approximation of derivative

Greetings,

Recently, I've read some papers in which they are using least-square to approximate the 2bd-order derivatives of a given 1-D data. I couldn't figure out how to do this, and I couldn't...
Forum: Main CFD Forum May 6, 2020, 23:36
Replies: 1
Views: 161
Posted By TurbJet
Eulerian transverse velocity increment

Hi,

I am reading paper [1], and I run into this formula for the Eulerian transverse velocity increment

\delta u_\perp = \|\mathcal{P}\cdot\delta u\|\cos\theta

where \mathcal{P} = \delta_{ij}...
Forum: Main CFD Forum January 30, 2020, 22:59
Replies: 23
Views: 956
Posted By TurbJet
Yeah, I know the ENO family. But from what I read...

Yeah, I know the ENO family. But from what I read (Chi-Wang Shu, ENO and WENO for hyperbolic conservation law, ICASE, 1997), under FVM framework, ENO/WENO only reconstruct the left/right face values,...
Forum: Main CFD Forum January 30, 2020, 14:15
Replies: 23
Views: 956
Posted By TurbJet
I went through Qiqi Wang's class at MIT (on...

I went through Qiqi Wang's class at MIT (on YouTube). His explanation of reconstruction is (if I understand him correctly) "directly interpolate the flux", rather than interpolate the face value then...
Forum: Main CFD Forum January 29, 2020, 16:38
Replies: 23
Views: 956
Posted By TurbJet
That makes sense. So can I presume that they are...

That makes sense. So can I presume that they are two different approaches to FVM?

Plus, is there any other higher order numerical flux? LeVeque extensively talks about Lax-Wendroff and...
Forum: Main CFD Forum January 29, 2020, 14:56
Replies: 23
Views: 956
Posted By TurbJet
Yeah, I saw that. I am just confused, as I said,...

Yeah, I saw that. I am just confused, as I said, we already have face values (from interpolation), why don't we directly assemble the flux use the face value? Why we need the numerical flux?
Forum: Main CFD Forum January 29, 2020, 01:02
Replies: 23
Views: 956
Posted By TurbJet
Reconstruction and flux approximation in FVM

Hi,

I've been reviewing the basic idea of FVM. However, there are few questions that I am confused. Lets take simple 1D linear advection for example
\frac{\partial q}{\partial t} +...
Forum: Main CFD Forum November 27, 2019, 02:31
Replies: 4
Views: 5,640
Posted By TurbJet
I just ignore the definition and directly use...

I just ignore the definition and directly use their conclusion.

The definition of mag(Omega) is given in the paper. But it seems to me the one you proposed is the same as theirs.
Forum: Main CFD Forum October 26, 2019, 19:34
Replies: 4
Views: 318
Posted By TurbJet
you are right, I am not looking for a GUI-way of...

you are right, I am not looking for a GUI-way of dealing with inputs. The other large code I am using is written in Fortran, it deals with the input in the way of writing an input-deck (script) and...
Forum: Main CFD Forum October 26, 2019, 19:31
Replies: 4
Views: 318
Posted By TurbJet
I totally agree that MATLAB is not the best way...

I totally agree that MATLAB is not the best way of practicing one's coding skill. The only reason I am using MATLAB is for the coding efficiency. My task at hand is more of a prove-of-concept, coding...
Showing results 1 to 25 of 206

 
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