I want to know correct method of analysis, velocity of air passes over the structure with height of 8m, when the velocity is converted to pressure loading. How much accuracy we may get it?. or Any other mode of transfer the load and find out max deflection of the structure within 4% of the height of structure.

ideal method, fluid structure interaction. fluid flow problem that also bends your part. not possible with solidworks simulation tools.

next best, decoupled FSI. run the fluid flow analysis to determine pressure loading, pass to solidworks simulation for analysis.

next best after that. determine the pressure generated by your fluid at velocity, apply as a pressure or force to your components.

to determine accuracy, write down the assumptions your method works and work out how different you think it may be. for example in #1 and #2 doesn't account for the change in the pressure when the structure changes. but that would potentially decrease the amount of deformation so you're actually working with a worst case loading with those methods.