Defining the Wing Flapping Cycle

The wing flapping motion is periodic, with a period of T=1/40 s. As the motion is periodic, it is convenient to define it with respect to a normalized time tFC that represents the fraction of the flapping cycle.

This normalized time, hereafter referred to as the flapping cycle time, can be defined as:
tFC=mod(t/T)T;0<tFC<1


For convenience, define the flapping period using a global parameter, which you can then reference when defining tFC and other time-dependent quantities:

  1. Right-click the Automation > Parameters node and select New > Scalar.
  2. Rename the parameter, FlappingPeriod, and set the following properties:
    Property Setting
    Dimensions Time
    Value 1/40
  3. To specify the number of time-steps per flapping cycle as a parameter:
    1. Create a scalar parameter as previously.
    2. Rename the parameter StepsPerCycle.
    3. Select the parameter and set the following properties:
      Property Setting
      Dimensions Dimensionless (default)
      Value 100
  4. To define the flapping cycle time tFC, you create an expression report:
    1. Right-click the Reports node and select New > User > Expression.
    2. Rename the report, FlappingCycleTime.
    3. Set the report properties as follows:
      Property Setting
      Dimensions Dimensionless (default)
      Definition mod(${Time},${FlappingPeriod})/${FlappingPeriod}
      Periodicity Non-periodic (default)
  5. Save the simulation.