error for gcloud permission

I recently has problem on uploading the file to gcloud services, so the solution is suggested as below

is add the username@ instances name

that solve the problem

Linux and aws

what the hell, keep facing the error cannot save text file under gedit in virtual box
so following the procedure here
https://unix.stackexchange.com/questions/52951/gedit-wont-save-a-file-on-a-virtualbox-share-text-file-busy

What fixed it for me (still a bit annoying but works), and is applicable to gedit, is to:

edit - preferences - editor Put a check on "Create backup copy"

When saving from now on, save the file once, ignore the error, save again. works every time.

note for using LINUX

haha, first time join a company using Linux, dont even know how to close the file using vi command
just press escape, it will go out of the text and go the last line, then press SHift +semi colon, thenit will appear, then you pressre q +exclamation, then last one, and omost important one, just press enter, then magic will appear.

happy to solve the problem.

also need to take note the OpenFOAM. just type writenow and save file, it will terminate immediately,


iyou can change start now from last time start. then it will start from lasttimestep.


useful vi command
https://www.cs.colostate.edu/helpdocs/vi.html

some thought

Recently decided to try CRIMSON installation, after I uninstall Virtural tool box and off the wifi, it start to run, so happy now,

finally run my model in CRIMSON software.


________________________________________________________________________

running OPENFOAM.
here is the good website to record
http://www.cfdyna.com/Home/openFOAM_Win.html

it has some protocol error, i guess it is just adminstrator problem
https://www.cfd-online.com/Forums/openfoam-installation/174281-got-error-while-copying-tutorial-files-local-directory.html
https://stackoverflow.com/questions/17895256/creating-symbolic-link-protocol-error

张量tensor的解释

张量tensor的解释
https://www.zhihu.com/question/36814916

小学课本上画杨桃的故事每个人都听过，一个杨桃在不同角度看，就会呈现不同的样子。有些物理量也是一样的，它在不同的角度看就会有不同的数值。比如对于一个矢量，你的基底变化了，矢量的表示也会变化。但是矢量的长度永远不变。
杨桃还是那个杨桃，物理量也还是那个物理量，但是一旦你换了个角度看，杨桃的形状就变了，物理量的数值也就变了。
那么如果一个物理系统没有一个更好的观察方向，或者说我们需要频繁的变换我们的视角的时候，应该怎么把握一个胡乱变化的东西呢？
你要记住，杨桃和物理量本身都是不变的，变的只是它在你眼中的形象。
于是张量就出现了，它将视角变换时候的变换关系作为张量的定义，看似在乱七八糟变，实际上只有满足这样的变换关系，它才是不变的！
研究一个看似乱七八糟变，实际上不变的东西，就是张量分析

作者：大野喵渣
链接：https://www.zhihu.com/question/36814916/answer/69248640
来源：知乎
著作权归作者所有，转载请联系作者获得授权。

residual in fluent

This is one of the best questions that anybody has posed in a while. As you've seen, it is sometimes not simple to declare convergence. Something that may help get the residuals down more, is to switch to double precision, and tweaking relaxation parameters may also help. Also, you need to consider the differencing scheme that you are using, and how accurate your initial flow field was. Something that sometimes helps is to get 0.0001 convergence on first order upwind differencing first, and then switch to higher order to see what it does. With external flows, where the initial flow field is normally a very good solution everywhere except near the body, it may also be difficult to get the requisite 0.001 convergence. For other flows 0.001 may not even be good enough. Take a very good look at how your surface integral changes with more iterations, sometimes if you really zoom in (in terms of y-axis scale), you can readily identify a damped oscillation, which is a good indication that you are "straddling" a converged answer. As last resort (or maybe that should be first?), work on your grid quality. If you have a number of skew or very high aspect ratio cells, perhaps away from your surface of interest, it may not affect your surface integral, but could affect the residuals.

http://www.cfd-online.com/Forums/fluent/44710-convergence-residuals.html

from bukit indah to singapore

visit jusco in tebrau
ohor的Bukit Indah离second link不远，属于新山的新区，新区的亮点就是人少，有个AEON购物中心，里面除了诸多商场外，还有一个电影院和超市吉之岛。另外距离AEON 10分钟的脚程，还有TESCO和Giant大卖场。额外突出的好处是Jurong East地铁站可以直接搭Causewaylink CW3 通过second link 直达Bukit Indah。 

just arrive in jurong east mrt, then you take causewaylink CW 3, after passing through 2nd link, you can arrive in bukit indah. then back, you just wait for CW 3 then you can go back  to singapore d .