Dynamic Derivatives#
Dynamic derivatives are essential coefficients that characterize an aircraft’s stability and control characteristics. Flow360 provides advanced capabilities for accurately computing these derivatives using time-accurate CFD simulations with prescribed motions. These derivatives are crucial inputs for flight dynamics models, control system design, and handling qualities assessment.
Learn techniques for setting up prescribed motion simulations to compute pitch, roll, and yaw dynamic derivatives and other stability parameters.
Key Concepts in Dynamic Derivative Analysis#
Static vs. dynamic stability coefficients
Frequency-dependent aerodynamic behavior
Small-perturbation vs. large-amplitude motions
Forced oscillation techniques in CFD
Linear vs. nonlinear aerodynamic modeling
Time domain and frequency domain analysis methods
Applications#
Dynamic derivatives are essential for numerous aerospace applications:
Flight dynamics model development and validation
Control system design and analysis
Flight simulator aerodynamic databases
Aircraft certification and regulatory compliance
Stability augmentation system design
Flutter and aeroelastic analysis
Handling qualities assessment
Simulation Approaches#
Flow360 supports various methods for computing dynamic derivatives:
Forced Oscillation Technique: * Prescribe sinusoidal motions (pitch, roll, yaw) * Extract in-phase and out-of-phase components * Determine frequency-dependent derivatives
Small Perturbation Method: * Apply small amplitude motions around trim conditions * Compute linear stability derivatives * Validate linear aerodynamic assumptions
Time-Domain System Identification: * Process time-history data from dynamic simulations * Extract derivatives using parameter estimation techniques * Build reduced-order models from high-fidelity CFD
Rotary Balance Simulation: * Model continuous rotation about body axes * Capture nonlinear aerodynamic damping effects * Predict spin characteristics and recovery