Ventilation grid with tesla valve "wave shape"

Integration of the tesla valve mechanic into a ventilation grid. The goal is to limit a counter flow of wind gust with the trade off of more obstruction of the forward flow (so making it more aerodynamic with a wave shape design).   

Printed in ASA with an inside skirt (kind of tedious to remove).  Fit into 100mm tube for my mechanical extractor.

Could be a print better with the layer line, if cut in half and print side way. 

I have not done simulations to search for the better ratio of the “wave shape” for specific velocity, it was a prototype and it solve my problem. A design with more wave like shape maybe suitable for more demanding application.

Since i have permanent forward flow from one side, and what i wanted is to counter gust from backflow. Gust are high flow from the other side and therefore tesla valve mechanic should be appropriate for this application. And after 1 year i can say i don't ear the gust in the tube and the fan reverse rotation anymore.

One reason i needed another design from my other design with flap check valve, is that the mechanical extractor output a low pressure flow that may not be enough to open the flap or it may limit to much the flow (which is not the problem for a ventilation hood that output high pressure flow). 

Another difference is that tesla valve let a slow flow pass, which is not a problem for a permanent mechanical extractor. But on a ventilation hood when not active, air can easily backflow so a auto closed check valve made more sense for better isolation.