fix: correct forumlar for dN_dr

yoctoyotta1024 · Apr 29, 2024 · ecb13e8 · ecb13e8
1 parent 7b243c3
commit ecb13e8
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Showing 3 changed files with 11 additions and 13 deletions.
diff --git a/libs/cartesiandomain/add_supers_at_domain_top.cpp b/libs/cartesiandomain/add_supers_at_domain_top.cpp
@@ -138,7 +138,8 @@ std::pair<size_t, double> CreateSuperdrop::new_xi_radius(const double gbxvolume)
   const auto log10r = double{log10rlow + frac * log10rwidth};
   const auto radius = double{Kokkos::pow(10.0, log10r)};
 
-  const auto numconc = droplet_numconc_distribution(radius, log10rwidth);
+  const auto binwidth = double{Kokkos::pow(10.0, log10rup) - Kokkos::pow(10.0, log10rlow)};
+  const auto numconc = droplet_numconc_distribution(radius, binwidth);
   const auto xi = (uint64_t)std::round(numconc * gbxvolume);  // cast double to uint64_t
 
   return std::make_pair(xi, radius);  // xi_radius
@@ -156,19 +157,16 @@ double CreateSuperdrop::new_msol(const double radius) const {
 }
 
 /* returns the droplet number concentration from a binned droplet number concentration
-distribution for a bin of width log10rwidth in log_10(r) space centred at radius. */
+distribution for a bin of width 'binwidth' (in radius space) centred at radius. */
 double CreateSuperdrop::droplet_numconc_distribution(const double radius,
-                                                     const double log10rwidth) const {
-  const auto dnumconc_dlnr = numconc * lognormal_pdf(radius);  // delta_numconc / delta_lnr
-  const auto dlnr = log10rwidth * std::log(10);  // convert delta_log10(r) into delta_ln(r)
-
-  return dnumconc_dlnr * dlnr;  // number of droplets per unit volume
+                                                     const double binwidth) const {
+  const auto dnumconc_dradius = numconc * lognormal_pdf(radius);  // delta_numconc / delta_radius
+  return dnumconc_dradius * binwidth;  // number of droplets per unit volume
 }
 
 /* normalised lognormal distribution returns the probability density of a given radius */
 double CreateSuperdrop::lognormal_pdf(const double radius) const {
-  const auto RADIUS = radius * dlc::R0;
-  const auto inverse_norm = RADIUS * sigtilda * std::sqrt(2.0 * std::numbers::pi);
-  const auto expo = (std::log(RADIUS) - MUtilda) / sigtilda;
+  const auto inverse_norm = radius * sigtilda * std::sqrt(2.0 * std::numbers::pi);
+  const auto expo = (std::log(radius) - mutilda) / sigtilda;
   return std::exp(-0.5 * expo * expo) / inverse_norm;
 }
diff --git a/libs/cartesiandomain/add_supers_at_domain_top.hpp b/libs/cartesiandomain/add_supers_at_domain_top.hpp
@@ -52,7 +52,7 @@ struct CreateSuperdrop {
   std::vector<double> log10redges; /**< edges of bins for superdroplet log_10(radius) */
   double dryradius;                /**< dry radius of new superdrop */
   double numconc;                  /**< number concentration of new droplets*/
-  double MUtilda;                  /**< ln(geometric mean) of lognormal distribution */
+  double mutilda;                  /**< ln(geometric mean) of lognormal distribution */
   double sigtilda;                 /**< ln(geometric sigma) of lognormal distribution */
 
   /* create spatial coordinates for super-droplet by setting coord1 = coord2 = 0.0 and coord3 to a
@@ -85,7 +85,7 @@ struct CreateSuperdrop {
         log10redges(),
         dryradius(config.DRYRADIUS / dlc::R0),
         numconc(config.NUMCONC * dlc::VOL0),
-        MUtilda(std::log(config.GEOMEAN)),
+        mutilda(std::log(config.GEOMEAN / dlc::R0)),
         sigtilda(std::log(config.geosigma)) {
     const auto log10rmin = std::log10(config.MINRADIUS / dlc::R0);
     const auto log10rmax = std::log10(config.MAXRADIUS / dlc::R0);

diff --git a/src/config/config.yaml b/src/config/config.yaml
@@ -81,6 +81,6 @@ boundary_conditions:
   DRYRADIUS: 1e-9                                      # dry radius of new super-droplets (for solute mass) [m]
   MINRADIUS: 1e-7                                      # minimum radius of new super-droplets [m]
   MAXRADIUS: 1e-4                                      # maximum radius of new super-droplets [m]
-  NUMCONC: 500e6                                       # number concentration of new droplets [m^-3]
+  NUMCONC: 1e9                                         # number concentration of new droplets [m^-3]
   GEOMEAN: 3.5e-6                                      # geometric mean radius of lognormal distribution [m]
   geosigma: 2.0                                        # geometric standard deviation of lognormal distribution