diff options
Diffstat (limited to 'core')
| -rw-r--r-- | core/dive.h | 1 | ||||
| -rw-r--r-- | core/gas-model.c | 10 | ||||
| -rw-r--r-- | core/planner.c | 12 |
3 files changed, 19 insertions, 4 deletions
diff --git a/core/dive.h b/core/dive.h index 8798b22ff..3a1492ed9 100644 --- a/core/dive.h +++ b/core/dive.h @@ -136,6 +136,7 @@ extern int units_to_sac(double volume); /* Volume in mliter of a cylinder at pressure 'p' */ extern int gas_volume(cylinder_t *cyl, pressure_t p); extern double gas_compressibility_factor(struct gasmix *gas, double bar); +extern double isothermal_pressure(struct gasmix *gas, double p1, int volume1, int volume2); static inline int get_o2(const struct gasmix *mix) diff --git a/core/gas-model.c b/core/gas-model.c index ad1160f3b..98139337c 100644 --- a/core/gas-model.c +++ b/core/gas-model.c @@ -62,3 +62,13 @@ double gas_compressibility_factor(struct gasmix *gas, double bar) */ return Z * 0.001 + 1.0; } + +/* Compute the new pressure when compressing (expanding) volome v1 at pressure p1 bar to volume v2 + * taking into account the compressebility (to first order) */ + +double isothermal_pressure(struct gasmix *gas, double p1, int volume1, int volume2) +{ + double p_ideal = p1 * volume1 / volume2 / gas_compressibility_factor(gas, p1); + + return p_ideal * gas_compressibility_factor(gas, p_ideal); +} diff --git a/core/planner.c b/core/planner.c index 118ad751d..7bbb7c0c4 100644 --- a/core/planner.c +++ b/core/planner.c @@ -246,7 +246,7 @@ static void update_cylinder_pressure(struct dive *d, int old_depth, int new_dept if (in_deco) cyl->deco_gas_used.mliter += gas_used.mliter; if (cyl->type.size.mliter) { - delta_p.mbar = gas_used.mliter * 1000.0 / cyl->type.size.mliter; + delta_p.mbar = gas_used.mliter * 1000.0 / cyl->type.size.mliter * gas_compressibility_factor(&cyl->gasmix, cyl->end.mbar / 1000.0); cyl->end.mbar -= delta_p.mbar; } } @@ -830,8 +830,11 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool volume = get_volume_units(cyl->gas_used.mliter, NULL, &unit); deco_volume = get_volume_units(cyl->deco_gas_used.mliter, NULL, &unit); if (cyl->type.size.mliter) { - deco_pressure = get_pressure_units(1000.0 * cyl->deco_gas_used.mliter / cyl->type.size.mliter, &pressure_unit); - pressure = get_pressure_units(1000.0 * cyl->gas_used.mliter / cyl->type.size.mliter, &pressure_unit); + int remaining_gas = (double)cyl->end.mbar * cyl->type.size.mliter / 1000.0 / gas_compressibility_factor(&cyl->gasmix, cyl->end.mbar / 1000.0); + double deco_pressure_bar = isothermal_pressure(&cyl->gasmix, 1.0, remaining_gas + cyl->deco_gas_used.mliter, cyl->type.size.mliter) + - cyl->end.mbar / 1000.0; + deco_pressure = get_pressure_units(1000.0 * deco_pressure_bar, &pressure_unit); + pressure = get_pressure_units(cyl->start.mbar - cyl->end.mbar, &pressure_unit); /* Warn if the plan uses more gas than is available in a cylinder * This only works if we have working pressure for the cylinder * 10bar is a made up number - but it seemed silly to pretend you could breathe cylinder down to 0 */ @@ -840,7 +843,8 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool translate("gettextFromC", "Warning:"), translate("gettextFromC", "this is more gas than available in the specified cylinder!")); else - if ((float) cyl->end.mbar * cyl->type.size.mliter / 1000.0 < (float) cyl->deco_gas_used.mliter) + if ((float) cyl->end.mbar * cyl->type.size.mliter / 1000.0 / gas_compressibility_factor(&cyl->gasmix, cyl->end.mbar / 1000.0) + < (float) cyl->deco_gas_used.mliter) snprintf(warning, sizeof(warning), " — <span style='color: red;'>%s </span> %s", translate("gettextFromC", "Warning:"), translate("gettextFromC", "not enough reserve for gas sharing on ascent!")); |