Linefollower airflow simulation

i did a quick and dirty check on how the undercarriage shape affects the pressure and thus the downforce. what i wanted to know was: can you assume that the pressure difference the fan creates is maintained under the entire hood, or is the vacuum decreasing towards the edges – and what kind of downforce can be expected?

i’ve learnt that the shape of the underside of the hood plays a major role in the downforce generated, as you can see in the picture bellow, the fan creates a difference of about 300Pa, but the major part of the undercarriage is only experiencing a mere 60 Pa pressure difference. more investigation needed!