Learning Forum

[AGAAMAZ]

hello every one

what is this part responsible for in the solar model in fluent , and how it affects the results ?

[Rob]

It's because x, y and z don't automatically align to North, or up. n

[AGAAMAZ]

nsorry sir , how can i determine the values of each one in North and East ?n

[Rob]

If you build the model in CAD, which way is North? It's usually written on the drawings. Take care to ensure you know the difference between site, true and magnetic north: if you ever find out why Civil Engineers need that many definitions please tell the rest of us! n

[AGAAMAZ]

nIf i want to put the solar still at initial position where its glass face directed to south then run the calculations nHow can i direct it in this direction? n

[peteroznewman]

nThis screen snapshot is from the ANSYS Help. North is +Y and East is +X that means up is +Z.nIf you use those values, then in CAD, draw your solar still so the X-Y plane is ground and Z is up. Draw the glass facing toward -Y and that is South.nIf you already drew your solar still and the X-Z plane was ground and Y is up, then if your glass was facing the -Z direction the values in the Mesh orientation would be n

[AGAAMAZ]

thanks sir that was helpfuln

[AGAAMAZ]

nbut for north z=1 or -1 in the other direction?.red face towards south nn

[peteroznewman]

nFor the red face to face south, the North column should have Z = -1 and the East column will have X = -1.n

[Rob]

strictly speaking won't North be z=-1 and y=-1 as it's about 45 degrees off both? n

[peteroznewman]

Array, mathematically and literally you are correct.nI was using the architectural meaning of the phrase facing south as in the structure is sitting on the ground and the side of the structure that has the window will face south, even though the window is tilted back about 45 degrees. I think that is what AGAAMAZ wants.n

[Rob]

we may both be right! It depends on whether it's the domain or the window is referring to. We've given both options so it's over to them. n

[AGAAMAZ]

@AGAAMAZ For the red face to face south, the North column should have Z = -1 and the East column will have X = -1./forum/discussion/comment/98533#Comment_98533

@peteroznewman, nthanks a lot for your concernnbut excuse me why X=-1 , isn't the east in the same direction of the +ve X-axis so we should put X=1 for East ?n

[AGAAMAZ]

nThanks a lot sirn Your clarification in this point helped me a lot .n

[peteroznewman]

nYes, you are right, X=1 for East if Z=-1 for North and +Y is Up.n

[alperen sevinc]

Hello,

We are conducting an analysis on solar still. We consider the gravitational direction as -9.81 in the Y direction. The geometry and coordinate axes are as shown in the figure.

1) What should be the mesh orientation? There are different opinions in the literature. I am asking this question to make sure.

2) For transient analysis, what should be the time step size and the total duration of the real analysis, and what do they depend on?

I would appreciate your assistance.

Thank you.