# How to transfer Pressure instead of Force in FSI?

**URL:** <https://precice.discourse.group/t/how-to-transfer-pressure-instead-of-force-in-fsi/688>\
**Category:** Using preCICE\
**Tags:** openfoam, adapters, fsi\
**Created:** [August 19, 2021, 7:42am UTC](https://precice.discourse.group/t/how-to-transfer-pressure-instead-of-force-in-fsi/688 "2021-08-19T07:42:42Z")\
**Posts on this page:** 1\
**Showing post:** 8

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**Author:** ![DavidSCN](https://avatars.discourse-cdn.com/v4/letter/d/c37758/32.png) [@DavidSCN](https://precice.discourse.group/u/DavidSCN)\
**Post date:** [August 22, 2021, 8:11am UTC](https://precice.discourse.group/t/how-to-transfer-pressure-instead-of-force-in-fsi/688/8 "2021-08-22T08:11:38Z")

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Ok, so again in order to make this clear: `Stress` data = the formula above = vector valued data, which is _not_ equal to `Pressure` data = scalar data, where the \tau\_{ij} is _not_ included. If you are still looking for an implementation of the above formula; the `Stress`data field includes this already.

Regarding your original question: OpenFOAM calls the pressure field and data just `p`, which exists as you can see. However, the constructor of the `Pressure` field you want to add takes the name (again, `p` by default) as an argument

```cpp
preciceAdapter::FSI::Pressure::Pressure(
    const Foam::fvMesh& mesh,
    const std::string nameP)

```

whereas you pass in the solver type

```cpp
        interface->addCouplingDataWriter(
            dataName,
            new Stress(mesh_, solverType_) /* TODO: Add any other arguments here */
        );

```

Have a look at these lines for a similar example [openfoam-adapter/FSI.C at 0c368d717bc5ec0fbd0aa4925c48a8164487fc3f · precice/openfoam-adapter · GitHub](https://github.com/precice/openfoam-adapter/blob/0c368d717bc5ec0fbd0aa4925c48a8164487fc3f/FSI/FSI.C#L60-L66)

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