[eng_shd]

Hi. I am doing a 2way fsi simulation in ansys fluent and transient structural about 2.5D membrane airfoil. z coordinate has only 1 element, and deflections in x and y axis just important. the picture attached.

the leading edge , lower part of middle of airfoil and small part of trailing edge are fixed and between them there is a flexible membrane in top (0.5mm thickness, 1500kg/m3 density and 80Mpa young module ). i set zero displacement in z coordinate for both thin symmetry plane of my geometry in structural and then define fluid solid interface. i used remeshing and smoothing for dynamic mesh.

but my problem: this membrane must have pre-strees in chord wise (300KPa) . how can i apply this prestress?