Leishman-Beddoes model definition
- @LEISHMAN_BEDDOES_MODEL_DEFINITION {
- @LEISHMAN_BEDDOES_MODEL_NAME {LsbModlName} {
- @ATTACHED_FLOW_DATA {
- @RECOVERY_COEFFICIENT {η}
- @TABLE_OF_INDICIAL_RESPONSE_COEFFICIENT {
- @MACH_NUMBER {Mach_{i}}
- @INDICIAL_RESPONSE_COEFFICIENTS {A_{1}, A_{2}, A_{3}, A_{4}, A_{5}}
- ...
- }
- @TABLE_OF_INDICIAL_RESPONSE_EXPONENTS {
- @MACH_NUMBER {Mach_{i}}
- @INDICIAL_RESPONSE_EXPONENTS {b_{1}, b_{2}, b_{3}, b_{4}, b_{5}}
- ...
- }
- @TABLE_OF_TIME_CONSTANT_MULTIPLIERS {
- @MACH_NUMBER {Mach_{i}}
- @TIME_CONSTANT_MULTIPLIERS {k_{1}, k_{2}, k_{3}, k_{4}}
- ...
- }
- @TABLE_OF_CM_CN_RATIO {
- @MACH_NUMBER {Mach_{i}}
- @CM_CN_RATIOS {k_{0}, k_{1}, k_{2}, m}
- ...
- }
- @AERODYNAMIC_CENTER_OFFSET {k_{0}}
- @SEPARATED_FLOW_MODEL {YES/NO}
- @T.E_SEPARATION_POINT_DATA {α_{1}, S_{1}, S_{2}}
- @SEPARATED_FLOW_MOMENT_DATA {k_{1}, k_{2}}
- @SEPARATED_FLOW_TIME_CONSTANTS {t_{p}, t_{f}}
- @VORTEX_EFFECT {YES/NO}
- @CRITICAL_NORMAL_FORCE_COEFFICIENT {C_{N1}}
- @VORTEX_TIME_CONSTANTS {t_{v}, t_{vl}}
- @CHORD_FORCE_DECAY_CONSTANT {Df}
- @COMMENTS {CommentText}
- }
- }
- }
NOTES
- The data required for the Leishman-Beddoes unsteady aerodynamic model is defined in this section.
- It is possible to attach comments to the definition of the object; these comments have no effect on its definition.
If flag @SEPARATED_FLOW_MODEL = YES the following data must be added.
- If flag @VORTEX_EFFECT = YES, Leishman-Beddoes vortex dynamic stall model is activated (if and only if @SEPARATED_FLOW_MODEL = YES).
- α_{1}, S_{1}, S_{2}, which are three empirical parameters which may be fitted to the test data for the T.E. separation point versus the angle of attack. α_{1} is closely correspond to the static stall angle of attack for most airfoil sections. They are input to the model in degrees.
- k_{1} k_{2} where k_{1} represents the direct effect on the center of pressure due to the growth of the separated flow region, and k_{2} helps describe the shape of the moment break at stall.
- t_{p} and t_{f} which are Mach number dependent time constants.
If flag @VORTEX_EFFECT = YES the following data must be added.
- The critical normal force coefficient C_{N1}, and can be obtained from the value of C_{N(static)} that corresponds to either the break in pitching moment or the chord force at stall.
- The vortex decay constant, t_{v}, and the center of pressure travel time constant t_{vl}.
- Df which is a constant that models empirically the increased rate at which the chord force is lost after the onset of the gross separation of flow in dynamic stall.