Pressure-gradient

Wall-normal relation

\[- \dmompre{1}\]

src/fluid/predict/ux.c

static int pressure (
    const domain_t * domain,
    const double * restrict p,
    double * restrict src
) {
  const int isize = domain->mysizes[0];
  const int jsize = domain->mysizes[1];
#if NDIMS == 3
  const int ksize = domain->mysizes[2];
#endif
  const double * restrict hxxf = domain->hxxf;
  BEGIN
    src[cnt] -= 1. / HXXF(i  ) * (
#if NDIMS == 2
        - P(i-1, j  )
        + P(i  , j  )
#else
        - P(i-1, j  , k  )
        + P(i  , j  , k  )
#endif
    );
  END
  return 0;
}

Stream-wise relation

\[- \dmompre{2}\]

src/fluid/predict/uy.c

static int pressure (
    const domain_t * domain,
    const double * restrict p,
    double * restrict src
) {
  const int isize = domain->mysizes[0];
  const int jsize = domain->mysizes[1];
#if NDIMS == 3
  const int ksize = domain->mysizes[2];
#endif
  const double hy = domain->hy;
  BEGIN
    src[cnt] -= 1. / hy * (
#if NDIMS == 2
        - P(i  , j-1)
        + P(i  , j  )
#else
        - P(i  , j-1, k  )
        + P(i  , j  , k  )
#endif
    );
  END
  return 0;
}

Span-wise relation

\[- \dmompre{3}\]

src/fluid/predict/uz.c

static int pressure (
    const domain_t * domain,
    const double * restrict p,
    double * restrict src
) {
  const int isize = domain->mysizes[0];
  const int jsize = domain->mysizes[1];
  const int ksize = domain->mysizes[2];
  const double hz = domain->hz;
  BEGIN
    src[cnt] -= 1. / hz * (
        - P(i  , j  , k-1)
        + P(i  , j  , k  )
    );
  END
  return 0;
}