Consistent density water default value. (#834)

Signed-off-by: Carlos Agüero <caguero@osrfoundation.org>

Author: caguero

vrx_gz/src/PolyhedraBuoyancyDrag.cc

@@ -164,7 +164,7 @@ class PolyhedraBuoyancyDrag::Implementation
   public: Wavefield wavefield;
 
   /// \brief The density of the fluid in which the object is submerged in kg/m^3
-  public: double fluidDensity = 997;
+  public: double fluidDensity = 1000.0;
 
   /// \brief The height of the fluid/air interface [m]. Defaults to 0.
   public: double fluidLevel = 0;

vrx_gz/src/Surface.cc

@@ -60,7 +60,7 @@ class vrx::Surface::Implementation
   public: double fluidLevel = 0;
 
   /// \brief Fluid density [kg/m^3].
-  public: double fluidDensity = 997.7735;
+  public: double fluidDensity = 1000.0;
 
   /// \brief The world's gravity [m/s^2].
   public: math::Vector3d gravity;

vrx_gz/src/Surface.hh

@@ -46,7 +46,7 @@ namespace vrx
   /// * `<vehicle_length>` is the length of the vessel [m].
   /// * `<hull_radius>` is the radius of the vessel's hull [m].
   /// * `<fluid_level>` is the depth at which the fluid should be in the vehicle
-  /// * `<fluid_density>` is the density of the fluid.
+  /// * `<fluid_density>` is the density of the fluid. Default value is 1000.
   /// * `<points>` contains a collection of points where the forces generated
   ///              by this plugin will be applied. See the format of each point
   ///              next: