corrected longitude computation

flash2d/src/options-sphere/ADV_wind_stacked.f90

@@ -501,6 +501,10 @@
 
       r_coord = grid_kartgeo(r_cart)
      
+!---------- correct lon coordinates to 0..360 degrees
+
+      IF(r_coord(1) .LT. 0_GRID_SR) r_coord(1)= r_coord(1)+ 360._GRID_SR
+
 !---------- find wind box corresponding to coordinate
 
       i_lox=1_GRID_SI