KR392: On Windows Vista machine, how can I activate scroll-bars when I select Gauge Variables in the AUTODYN GUI? |
User should check the system settings in their Windows Vista machine.<br><br>Click on "Start -> Control Panel -> System and Maintenance -> System ->... |
KR393: What turbulence model should I use to model gas-solid fluidized bed in FLUENT? |
For modeling gas-solid fluidized beds, we recommend that you do not use any turbulence model. Please run your cases laminar.<br><br>In any gas-solid fluidized bed, including bubbling... |
KR394: I get error message when I try to save the data after zone reactivation in FLUENT. Why? |
If you initialize the solution after deactivating the zone, you will get error when you try to save the data file. You are not able to write the data because there is no data present for the... |
KR395: How do I make a 'copy' of an existing variable in CFD-Post? |
Under the Quantitative tab, create an expression.<br><br>For the expression value, enter the name of the variable to be copied.<br><br>Under the Variables tab, do a mouse... |
KR396: How to change aspect ratio of a given model in CFD-Post? |
This feature is required if you want to zoom in a particular direction while maintaining visibility of the entire model. So, if you want to check temperature contours on the surface of a long... |
KR398: How to retrieve the values of specific variables at the nodes of your mesh? (Solution ID: 1413) |
It is sometimes necessary to retrieve the values of specific variables at the nodes of your mesh. This could be done by looping over cells/faces and accessing the interpolated data at the... |
KR399: How to calculate wall shear stress using a User-Defined Function (UDF)?(Solution ID: 1459) |
The UDF below shows a strategy to compute and use wall shear stresses. It loops over all the faces of the wall boundary on which the wall shear stress has to be obtained. The wall shear stress is... |
KR400: How can we ""flag"" the cell which has reverse flow (backflow)?(Solution ID: 1351) |
This UDF will "flag" the cells which have reverse flow, thus enable us to uniquely see which cells have reversed flow. This is particularly useful if the surface is complex and does... |
KR401: How can we read the experimental/tabulated values of material properties or profiles using a UDF? (Solution ID: 1338) |
FLUENT provides for a variety of methods for specifying material properties, including polynomial functions, piece-wise linear functions, etc. User-defined functions can also be used to specify... |
KR402: How to compute the integral of a variable along a line using UDF in FLUENT? (Solution ID: 1293) |
Line surfaces in FLUENT have area in 2d and 2d-axi but not in 3d, so currently integrals on line surfaces are zero.<br><br>This solution provides a sample User Defined Function (UDF)... |
KR403: Output from a UDF using Message() only prints to the GUI. If the output is desired to go to a file, the fprintf function is commonly used. How can one easily switch between the two without having a lot of duplicate lines in the FLUENT UDF code? (Solution ID: 1175) |
A single function is given to combine the two. This function, generically is called gf_print(FILE*, char* format, ...).<br><br>The first argument, if NULL, will direct the output to... |
KR404: How to generate a step-by-step particle tracking report file from a calculation running in batch mode? (Solution ID: 1263) |
Use the following UDF to write the file.<br><br>Steps:<br>1. Compile the UDF<br><br>2. Hook the UDF to the DPM_SCALAR_UPDATE hook located on the dpm model... |
KR405: How can my UDF write output files with the flow time as part of the file name in FLUENT? (Solution ID: 1105) |
A common request from users is for the name of output files written from a UDF to be appended with the flow time. This may be confusing for someone who has no formal training in C-programming,... |
KR406: How to determine the amount of time fluid spends in high shear regions? (Solution ID: 1072) |
For certain applications (e.g., liquid-liquid multiphase reactors, bioreactors), the amount of time the fluid spends in the high strain regions near impellers and baffles is a key parameter. The... |
KR407: How to compute the slip velocity of the particles in DPM model using a UDF? (Solution ID: 920) |
A UDF is written to compute the slip velocity of the particles in dpm model. Say for example in any internal surface (through which particles are passing) user wants to find the value of (V_p -... |
KR408: How to calculate/report torque acting on a rotor's shaft using a UDF? (Solution ID: 917) |
Torque acting on a shaft is always an important quantity user often wants to calculate and monitor from a simulation. Fluent post processing REPORT panel allows users to report moment of the face... |
KR409: How to obtain particles' mean diameters at each cell in a spray simulation? (Solution ID: 830) |
In spray simulations, users often want to obtain the particles size distribution. For example, a contour plot of D32 (Sauter Mean diameter) over a plane would be very helpful in understanding the... |
KR410: How to handle a moving porous medium in Fluent? (Solution ID: 831) |
Moving porous media appears in many industrial applications. Since they are moving, they will induce the surrounding fluid to flow with them, at the same time, since they are porous, fluid can... |
KR411: How to compute fluid residence time using UDF? (Solution ID: 619) |
We can compute fluid residence time via UDF using user-defined scalars. Source code for UDF is below.<br>1. Compile udf<br>2. Read case.... set # UDS > 0<br>3. At... |
KR412: How can we compute fan pressure drop as a function of radial distance from the center of rotation of the fan (and flow kinetic energy)? (Solution ID: 508) |
This solution consists of the following files:<br><br>* jump.c = UDF to compute dp across fan as a function of (distance from fan center) and flow ke.<br><br>* ... |
KR413: How can we compute radiation heat rate on an interior surface using UDF? (Solution ID: 669) |
The UDF loops through all DO directions for each face on the surface, and depending on the s dot n sign it picks up the radiative intensity "upstream" of the surface so that only... |
KR414: How can we compute turbulent diffusion coefficient for UDS? (Solution ID: 668) |
Solution methodology is as follows<br><br>if turbulence is not on, then<br>rho D = rho (D_lam)<br><br>otherwise<br><br>rho D = rho (D_lam + ... |
KR415: How can we access values calculated by a custom field function inside a UDF? (Solution ID: 512) |
Sometimes, for some reason, the user wants to use values that are available in post-processing (through e.g. "Display---Contours" and all the other post-processing functions) inside... |
KR416: How can we calculate radial, tangential and axial velocity components in UDFs? (Solution ID: 562) |
A user wants to apply an energy source term that is function of radial velocity. Since only velocities in Cartesian coordinates are available through UDF, this routine was created to calculate... |
KR417: How can we read (interpolate) source term from point data input file not aligned with grid? (Solution ID: 625) |
User has source terms (for energy eqn) that are not aligned with grid. How can this source term data be interpolated.<br>The solution is several steps and involves a UDF (that should be... |