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authorGravatar Rick Walsh <rickmwalsh@gmail.com>2015-08-29 21:34:19 +1000
committerGravatar Dirk Hohndel <dirk@hohndel.org>2015-08-29 20:06:35 -0700
commitbecc1e6dc417765670fec7d49e955cb0b3edbb23 (patch)
tree29f102f16c23b1f841880adf09581819f3287ca3 /deco.c
parent1e7dd492345c903b4009590e5d1deae3ce911c43 (diff)
downloadsubsurface-becc1e6dc417765670fec7d49e955cb0b3edbb23.tar.gz
VPM-B: Use correct gamma values
In other implementations of VPM-B, surface_tension_gamma and skin_compression_gammaC are taken as 0.0179 N/msw and 0.257 N/msw respectively. We do pressure calculations in bar, not msw, so our gamma values need to reflect that. Previously we had used 0.179 and 2.57, which are close but not quite correct (10 msw == 1.01325 bar). Signed-off-by: Rick Walsh <rickmwalsh@gmail.com> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Diffstat (limited to 'deco.c')
-rw-r--r--deco.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/deco.c b/deco.c
index 7a9f33e5a..a9dbf4cfa 100644
--- a/deco.c
+++ b/deco.c
@@ -52,8 +52,8 @@ struct vpmb_config {
double crit_radius_He; //! Critical radius of He nucleon (microns).
double crit_volume_lambda; //! Constant corresponding to critical gas volume (bar * min).
double gradient_of_imperm; //! Gradient after which bubbles become impermeable (bar).
- double surface_tension_gamma; //! Nucleons surface tension constant (N / 10m).
- double skin_compression_gammaC; //! Skin compression gammaC (N / 10m).
+ double surface_tension_gamma; //! Nucleons surface tension constant (N / bar = m2).
+ double skin_compression_gammaC; //! Skin compression gammaC (N / bar = m2).
double regeneration_time; //! Time needed for the bubble to regenerate to the start radius (min).
double other_gases_pressure; //! Always present pressure of other gasses in tissues (bar).
};
@@ -63,8 +63,8 @@ struct vpmb_config vpmb_config = {
.crit_radius_He = 0.45,
.crit_volume_lambda = 199.58,
.gradient_of_imperm = 8.2,
- .surface_tension_gamma = 0.179,
- .skin_compression_gammaC = 2.57,
+ .surface_tension_gamma = 0.18137175, // = 0.0179 N/msw
+ .skin_compression_gammaC = 2.6040525, // = 0.257 N/msw
.regeneration_time = 20160.0,
.other_gases_pressure = 0.1359888
};