[narcker]

CEL language has a "Conditional If Statement", which use the following syntax: if( cond_expr, true_expr, false_expr ) .
I want to define the " true_expr " as a vector if the conditional test is true. But I do not know how to write the "true_expr" as a vector (in cartesian coordinate system and cylindrical coordinate system)?
Give an example,
**********************
if(z>1&&z<2&&30[degree]<theta&&theta<(60[degree])*180/pi),100[N/m^3] ,0[N/m^3]))
*************************
I want to change the "100[N/m^3]" to "F=k1*Fx+K2*Fy", and then transform it to cylindrical coordinate system. ps. Fx and Fy are vectors.

Thank you for your time reading this and looking forward to your reply.

[Opaque]

Your question is a bit vague on what you are trying to achieve. The functionality is very clear that is takes a logical expression, and evaluate two scalar expressions.

Are you trying to satisfy 3 conditions at once ?, i.e. every component of the cylindrical vector .

For complex expressions, I usually break them down to simple expressions, so the conditional is easier to read

if (a && b && c, MyTrueResult, MyFalseResult)

MyTrueResult = ....
MyFalseResult = ...

That helps to also separate the Cartesian to cylindrical conversions such as

MyRadialComp = MyCart X * ... + MyCart Y * .. + MyCart Z * ...
MyThetaComp = MyCart X * ... + MyCart Y * .. + MyCart Z * ...
MyAxialComp = MyCart X * ... + MyCart Y * .. + MyCart Z * ...

Keep in mind that you can actually access the components of a vector my suffixing _x, _y, or _z to the variable name. For example, MyVar_x is the X component of variable MyVar. Similar to force_x, force_y, etc..

Hope the above helps,

[narcker]

Thank you for your reply.
Your explanation is very clearly.
But, there is a question really bothers me.
Now, I want to add a body force into the flow field, and the area of body force have been given at " cond_expr " under cylindrical coordinate system.

*********************************************
The "Conditional If Statement" is as follows,
if(z>1&&z<2[m] && 30[degree]<theta&&theta<(30[degree]+(3[mm]/(r+0.000001[mm]))*180/pi) &&(-z*tan(pi/18))<r&&r<(-z*tan(pi/18)+1.5[mm]), BODYFORCE [N/m^3] ,0[N/m^3]))
************************************************** ***
The total body force is as follows,
BODYFORCE = BODYFORCE _x+ BODYFORCE _y
BODYFORCE _x= k1*exp (-((x-x0-(y-y0))/y)^2-k2*(y-y0)^2)
BODYFORCE _y=k3*exp(-((x-x0)/y)^2-k4*(y-y0)^2)
**********************************************
I do not know how can I put the cartesian vector BODYFORCE into the " Conditional If Statement ", in which the " cond_expr " are written under cylindrical coordinate system.
Maybe I should change the BODYFORCE into cylindrical conversions firstly.
And is there suffixing _r, _theta, or _z in cylindrical coordinate system like _x, _y and _z in cylindrical coordinate system.
Looking forward to your reply.

[narcker]

Thank you for your reply.
Your explanation is very clearly.
But, there is a question really bothers me.
Now, I want to add a body force into the flow field, and the area of body force have been given at " cond_expr " under cylindrical coordinate system.

*********************************************
The "Conditional If Statement" is as follows,
if(z>1&&z<2[m] && 30[degree]<theta&&theta<(30[degree]+(3[mm]/(r+0.000001[mm]))*180/pi) &&(-z*tan(pi/18))<r&&r<(-z*tan(pi/18)+1.5[mm]), BODYFORCE [N/m^3] ,0[N/m^3]))
************************************************** ***
The total body force is as follows,
BODYFORCE = BODYFORCE _x+ BODYFORCE _y
BODYFORCE _x= k1*exp (-((x-x0-(y-y0))/y)^2-k2*(y-y0)^2)
BODYFORCE _y=k3*exp(-((x-x0)/y)^2-k4*(y-y0)^2)
**********************************************
I do not know how can I put the cartesian vector BODYFORCE into the " Conditional If Statement ", in which the " cond_expr " are written under cylindrical coordinate system.
Maybe I should change the BODYFORCE into cylindrical conversions firstly.
And is there suffixing _r, _theta, or _z in cylindrical coordinate system like _x, _y and _z in cylindrical coordinate system.
Looking forward to your reply.

[Opaque]

Unfortunately, the variable indexing does not include cylindrical component ones. You will be on your own having to do the conversions.

Also, you can only use expressions that resolve to a scalar anywhere in CEL; therefore, vectors must be handled component wise (unroll, or split in simpler expressions)

Hope the above helps,