View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0004243 | OpenFOAM | Bug | public | 2025-06-10 14:39 | 2025-06-10 15:09 |
| Reporter | otaolafr | Assigned To | henry | ||
| Priority | normal | Severity | trivial | Reproducibility | always |
| Status | closed | Resolution | no change required | ||
| Platform | GNU/Linux | OS | Other | OS Version | (please specify) |
| Product Version | 12 | ||||
| Summary | 0004243: nu0 for non newtonean fluids not clearly defined | ||||
| Description | I just migrated to OFv12 and addapting myself to the new structure of the code. I wanted to implement non-newtonean fluid to a multiphase flow more specifically CrossPowerLaw to the liquid fluid. following the instruction from CrossPowerLaw.C (and tutorial) one needs to add the following variables to the momentumTransport.liquid ``` laminar { model generalisedNewtonian; viscosityModel CrossPowerLaw; nuInf 1.08e-3; m 1.768; n 0.6812; } ``` Here the nu0 is not defined here (and the solver will run, and furthemore it will mention that it will use crossPowerLaw, neverthless nu0 is missing. if we have a look at the crossPowerLaw.C it mentions: `Note the viscosity nu0 at zero strain rate is a physical property, generally specified in the physicalProperties file` but in the physicalProperties.liquid this viscosity is not mentioned. I tried to find where this is calculated, I imagine that the nu0=mu/rho (with rho calculated from the equationOfState and the mu, the one on transport. after a lot of digging in the code i could not find where this field came from. from outputing the fild during the simulation, it looks like it is calculated like that. would be nice to better explain in the note of the .C files this. something like: Note that the nu0 is calculated from the mu and rho calculated from the transport and equationOfState of the physicalProperties file. this would be much clear, especially since there are a test case https://github.com/OpenFOAM/OpenFOAM-12/blob/0f458291f1cd6b7afff839eab96d838d6a9e95c2/test/boundaryLayer/boundaryNonNewtonian/constant/momentumTransport#L27 where there is mentionned in the dictionary a nu0 (that it is not read by the .C file. | ||||
| Tags | No tags attached. | ||||
