View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0004156 | OpenFOAM | Bug | public | 2024-09-26 13:48 | 2024-09-26 15:46 |
| Reporter | Tobermory | Assigned To | henry | ||
| Priority | low | Severity | trivial | Reproducibility | always |
| Status | resolved | Resolution | fixed | ||
| Platform | GNU/Linux | OS | Other | OS Version | (please specify) |
| Product Version | 12 | ||||
| Fixed in Version | dev | ||||
| Summary | 0004156: documentation in the totalPressureFvPatchScalarField header | ||||
| Description | The documentation at the top of the totalPressureFvPatchScalarField.H file lists G as a parameter for the compressible supersonic case (case 4). The equation for the patch pressure is correct, but the definition of G is wrong in the text below: it states G = gamma/(1 - gamma). However, lines 73-78 of dynamicPressureFvPatchScalarField.C read: const scalar gM1ByG = (gamma_ - 1)/gamma_; operator== ( p0p/pow(scalar(1) - psip*gM1ByG*K0mKp, 1/gM1ByG) ); This coding is correct, and suggests that two changes are needed in the header documentation: - the definition of G should ideally read: G = (gamma - 1)/gamma, to match the code - a minus sign is needed in front of the G in the denominator of the expression for the case 4 patch pressure pp = p0 / [ 1 - G psi(...)]^(1/G) For the latter, you could keep the plus sign in front of the G, but you will then need a negative sign in the 1/G exponent, so simplest is just to match the coding. | ||||
| Additional Information | A further minor point to consider is that the use of gamma to specify both the compressibility regime and the specific heat ratio is a bit confusing ... until you look at the code. Can I suggest a trivial addition to the text in the 4th para, changing: "The patch pressure is evaluated from the external conditions using one of the following expressions depending on the flow conditions and specification of compressibility:" to "The patch pressure is evaluated from the external conditions using one of the following expressions depending on the flow conditions and specification of compressibility (which is implemented through the gamma parameter):" Alternatively, or in addition, change "3. compressible transonic ( gamma = 1):" "4. compressible supersonic ( gamma > 1):" to "3. compressible transonic ( set gamma = 1):" "4. compressible supersonic ( set gamma > 1):" | ||||
| Tags | No tags attached. | ||||
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2024-09-26 13:48 | Tobermory | New Issue | |
| 2024-09-26 15:46 | henry | Assigned To | => henry |
| 2024-09-26 15:46 | henry | Status | new => resolved |
| 2024-09-26 15:46 | henry | Resolution | open => fixed |
| 2024-09-26 15:46 | henry | Fixed in Version | => dev |
| 2024-09-26 15:46 | henry | Note Added: 0013418 |
