Results of a new version of the LTRAN2-NLR code (LTRANV) for unsteady viscous transonic flow computations

Results of a new version of the LTRAN2-NLR code (LTRANV) for unsteady viscous transonic flow computations

Houwink, R.

National Aerospace Laboratory NLR

1981-07-07

An outline is given of a first version of the computer programme LTRAFV for coupled unsteady transonic flow/turbxilent boundary layer computations. It is a combination of the LTRAN2-NLR programme and the lagentrainment method of Green. A comparison is made of theoretical and experimental results for the NACA64A006 airfoil with oscillating flap in subsonic and transonic flow. Accounting for the effect of the boundary layer on the airfoil yields a reduction of the magnitude of unsteady airloads by 10-35 % and a phase shift of 2 to 7 degrees. As a result, a generally better agreement with experimental data is obtained. Considerable differences between theory and experiment at low reduced frequency are likely due to strong wall interference effects and some underestimation of the boundary layer effect. The use of a steady boundary layer method instead of an unsteady one is acceptable for the cases considered

Computational fluid dynamics
Viscous flow
Unsteady flow
Transonic flow
Computer programs
Aerodynamic coefficients
Wing oscillations
Flaps
Thin airfoils
Pressure distribution
Lift

http://resolver.tudelft.nl/uuid:298cc04a-77a6-482b-93a7-a4004db7a035

Nationaal Lucht- en Ruimtevaartlaboratorium

Campus only

NLR-TR 81078 U

Aerospace Engineering Reports

report

(c)1981 National Aerospace Laboratory NLR