[immortality]

although rhoPimpleFoam writes residuals of continuity equation but rhoCentralFoam doesn't (why?).
then how can change rhoCentralFoam to write continuity residuals like variable residuals?
writing part of them is like below:
rhoCentralFoam:

     turbulence->correct();          runTime.write();          Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"             << "  ClockTime = " << runTime.elapsedClockTime() << " s"             << nl << endl;     }      Info<< "End\n" << endl;      return 0; }

rhoPimpleFoam:

     if (pimple.turbCorr())             {                 turbulence->correct();             }         }          runTime.write();          Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"             << "  ClockTime = " << runTime.elapsedClockTime() << " s"             << nl << endl;     }      Info<< "End\n" << endl;      return 0; }

looks like the same.