How does E+ determine the win pressure coefficients on surface facing an internal yard within the building? [closed]

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We model a rectangular building with an internal yard (open to the sky) and windows facing this yard. In order to evaluate the effect of natural ventilation we run the fully calculated ventilation option. From the Engineering Reference document, it is not clear how E+ treats the wind pressure coefficients on the surfaces that face the yard. It seems that it will use the same coefficients as on the externally exposed surfaces in the same direction, which is not correct, and would cause wrong patterns of air flows. In particular, the surface that is in the wind direction would be treated as if it is exposed to the positive wind pressure instead of being exposed to suction.