ORNISP

An Integrated Design Environment for Flapping Flight

ORNISP combines model preparation, automatic RecurDyn model creation, aerodynamic simulation and post-processing for ornithopter design.

ORNISP V2 model preview with a three-dimensional aircraft model and plan-view aerodynamic mesh.

01 Model Data Management

Create a new model or open an existing configuration.

ORNISP V2 New Model dialog with a model name field and simulation model list.

02 Model Parameter Setting

Define the main wing, tail wing, and body, then set their design parameters and wing kinematics. Geometry and motion previews help inspect the configuration before model creation.

Main wing, tail wing and body parameters with material properties and wing kinematics in ORNISP V2.

03 Simulation Setting

Set the flapping frequency, number of cycles, time resolution, and aerodynamic model options. Review the model summary and select the wake data to retain for post-processing.

Flapping frequency, cycle count, time step, aerodynamic model options and model checks in ORNISP V2.

04 Automatic Model Creation

Python uses RecurDyn ProcessNet to generate the aircraft model from the configured inputs.

RecurDyn viewport during automatic construction, showing the body and tail of the model.

The model below is from a separate research case.

Representative ornithopter simulation model in an oblique view and a side view with its mass center marked.

05 Aerodynamic Simulation

The modified Unsteady Vortex Lattice Method (UVLM) computes aerodynamic loads while RecurDyn solves the aircraft dynamics.

Recorded aerodynamic simulation in RecurDyn with the aircraft wing pose and displayed load vectors.

Flapping-wing motion and aerodynamic load vectors in RecurDyn.

06 Post-Processing

Post-processing tools display the wake, forces, moments and crank driving torque. The Plot Tool compares selected cases on the same axes.

ORNISP V2 Plot Tool comparing crank driving torque for Example_Rigid and Example_Flexible.

ORNISP V2 post-processing workspace displaying the aircraft and its wake.

Aerodynamic Methods

UVLM represents the wing and its wake with vortex elements. ORNISP extends this representation with the Pseudo-Leading-Edge Vortex (PLEV) method and Adaptive Wake-Shedding (AWS) scheme.

Unsteady Vortex Lattice Method

UVLM places bound vortex rings on the wing and free vortex rings in the wake. Collocation points are where the panel boundary condition is evaluated.

UVLM schematic showing collocation points, bound vortex rings, free wake vortex rings, coordinates and circulation symbols.

Pseudo-Leading-Edge Vortex

PLEV introduces a prescribed vortex ring near the leading edge to represent selected leading-edge vortex effects.

PLEV leading-edge panel schematic and its connected detail in the aerodynamic model.

Adaptive Wake-Shedding

AWS partitions circulation between a residual edge ring and shed wake elements according to local flow alignment.

In the schematic, WSE means Wake Shedding Edge. The blue arrow shows the velocity induced at the panel collocation point; the dark green rings are vortex-ring elements.

AWS schematic showing the wake shedding edge, blue induced-velocity arrow at the panel collocation point, and dark green vortex-ring elements.

Program Structure

The MATLAB interface prepares the model inputs and displays results. Python ProcessNet automates RecurDyn model generation, while the Fortran aerodynamic solver exchanges loads and motion with RecurDyn dynamics.

Architecture connecting the MATLAB interface, Python ProcessNet model generation, RecurDyn dynamics and Fortran aerodynamic solver.