21 research outputs found
Linear Frequency Domain Method for Load Control by Fluidic Actuation
Simulations of periodic fluidic excitations in the context of active flow control are per-
formed using a frequency domain solver for the efficient prediction of global air loads.
Frequency domain methods have become a viable choice whenever the disturbance of the
flow is small and periodic, and can reduce the computational effort substantially in compar-
ison to time-accurate unsteady simulations. Although time-accurate unsteady simulations
resolve the entire spectrum of the flow, they suffer from a long transient phase and thus
require an extensive use of computational resources. The goal is to extend the time-
linearized frequency domain method of the DLR TAU-code toward load control by blowing
fluidic actuators. This paper presents the set of discretized unsteady equations and as-
sociated boundary conditions for both the time accurate and frequency domain method.
The applied time-linearized frequency method decouples each harmonic, forming a linear
approach, which renders the sequential calculation of the individual harmonics to evaluate
the time response of air loads. At first, blowing actuation for a two-dimensional airfoil with
a single slot is considered for which constant as well as periodic excitations are used for
validation and investigation purposes of air loads between the time-accurate and nonlinear
frequency domain method. In addition, a 2-element high-lift wing with a flow separation
on the trailing edge flap is simulated that demonstrates the good prediction quality of air
load derivatives with the frequency domain method