Actuator source prototype (Exawind#298)

- Use AMR particles to perform search and interpolation of velocities for use with actuator line/disk simulations

- Introduces skeleton data structures that will be used to create different actuator source types (wing, turbine) and combined with different types of actuator forcing representations (line, disk)

amr-wind/core/gpu_utils.H

@@ -0,0 +1,21 @@
+#ifndef GPU_UTILS_H
+#define GPU_UTILS_H
+
+#include "AMReX_Gpu.H"
+
+namespace amr_wind {
+namespace gpu {
+
+template <typename T>
+inline amrex::Gpu::DeviceVector<T> device_view(const amrex::Vector<T>& hview)
+{
+    amrex::Gpu::DeviceVector<T> dview(hview.size());
+    amrex::Gpu::copy(
+        amrex::Gpu::hostToDevice, hview.begin(), hview.end(), dview.begin());
+    return dview;
+}
+
+} // namespace gpu
+} // namespace amr_wind
+
+#endif /* GPU_UTILS_H */

amr-wind/wind_energy/CMakeLists.txt

@@ -9,3 +9,5 @@ target_sources(${amr_wind_lib_name}
   ABLBoundaryPlane.cpp
   MOData.cpp
   )
+
+add_subdirectory(actuator)

amr-wind/wind_energy/actuator/ActuatorContainer.H

@@ -0,0 +1,103 @@
+#ifndef ACTUATORCONTAINER_H
+#define ACTUATORCONTAINER_H
+
+#include "amr-wind/core/vs/vector_space.H"
+
+#include "AMReX_AmrParticles.H"
+
+namespace amr_wind {
+
+class Field;
+
+namespace actuator {
+
+/** Cloud of actuator points
+ *
+ *  Holds the position vector and velocity information for a cloud of actuator
+ *  points belonging to all the turbines within a given MPI rank.
+ */
+struct ActuatorCloud
+{
+    //! Number of nodes per turbine on this MPI rank
+    amrex::Vector<int> num_pts;
+
+    //! Position vectors of all actuator nodes belonging to this MPI rank
+    amrex::Vector<vs::Vector> position;
+
+    //! Velocity vectors of all actuator nodes belonging to this MPI rank
+    amrex::Vector<vs::Vector> velocity;
+
+    //! Total number of turbines located on this MPI rank
+    int num_objects;
+
+    explicit ActuatorCloud(const int nobjects);
+};
+
+//! Number or real entries in Array of Structs (AOS)
+static constexpr int NumPStructReal = AMREX_SPACEDIM;
+//! Number of integer entries in Array of Structs (AOS)
+static constexpr int NumPStructInt = 0;
+//! Number of real entries in Struct of Arrays (SOA)
+static constexpr int NumPArrayReal = 0;
+//! Number of int entries in Struct of Arrays (SOA)
+static constexpr int NumPArrayInt = 0;
+
+/** Specialization of AmrParticleContainer for sampling velocities
+ */
+class ActuatorContainer
+    : public amrex::AmrParticleContainer<
+          NumPStructReal,
+          NumPStructInt,
+          NumPArrayReal,
+          NumPArrayInt>
+{
+public:
+    explicit ActuatorContainer(amrex::AmrCore& mesh, const int num_objects);
+
+    void post_regrid_actions();
+
+    void initialize_container();
+
+    void update_positions();
+
+    void sample_velocities(const Field& vel);
+
+    int num_actuator_points() const { return m_data.position.size(); }
+
+    // public for CUDA, not safe for general access
+
+    void interpolate_velocities(const Field& vel);
+
+    void populate_vel_buffer();
+
+protected:
+    void compute_local_coordinates();
+
+    // Accessor to allow unit testing
+    ActuatorCloud& point_data() { return m_data; }
+
+private:
+    amrex::AmrCore& m_mesh;
+
+    // Object that holds the position and velocity information
+    ActuatorCloud m_data;
+
+    //! Coordinates of points that are contained within boxes assigned to each
+    //! MPI rank
+    amrex::Vector<vs::Vector> m_proc_pos;
+
+    //! Device view of the process position vectors
+    amrex::Gpu::DeviceVector<vs::Vector> m_pos_device;
+
+    //! Flag indicating whether memory has allocated for all data structures
+    bool m_container_initialized{false};
+
+    //! Flag indicating whether the particles are scattered throughout the
+    //! domain, or if they have been recalled to the original MPI rank
+    bool m_is_scattered{false};
+};
+
+} // namespace actuator
+} // namespace amr_wind
+
+#endif /* ACTUATORCONTAINER_H */