I am writing the code of FEM applied to lubrication problem in Matlab. I found little introduction of boundary conditions in the circumferential direction of finite width journal bearing in many reference literature. Without consideration of circumferential boundary condition, one pressure distribution can be solved then the negative pressure should be set zero which represent oil film rupture. But when I change the deviation angle 📷，the calculated pressure distribution also changed, and even appeared the positive pressure distribution in whole circumferential domain( 360 degree) which is apparently irrational. I think that the solution domain should be restricted in complete film domain rather than full circumferential domain ( 360 degree). The reason is that Reynolds equation is not applicable for oil film rupture (cavitation) domain. Therefore,
It is necessary to calculate the position of oil film rupture. Alternatively, full Somerfield condition or half Somerfield condition can be adopted to do this easily. But Reynolds condition is difficult to applied to FEM, Furthermore, which is even more so in the case stepped cavity journal bearing or herringbone groove bearing.
So, my question is：Is it necessary to consider the fluid film rupture in the circumferential direction not only consider axial side boundary condition? If it is necessary, how treat the Reynolds boundary?
Have a look at https://www.sciencedirect.com/topics/engineering/rotational-reynolds-number
https://books.google.com.au/books?id=QcnBDwAAQBAJ&pg=PA64&lpg=PA64&dq=Reynolds+boundary+conditions+in+the+circumferential+direction&source=bl&ots=s3i26QiGI2&sig=ACfU3U0IRQ1N5WqDJx1awK-3ONOwpPYM6Q&hl=en&sa=X&ved=2ahUKEwj4vtqc16vqAhUJwjgGHe0fBfcQ6AEwEHoECAYQAQ&authuser=1#v=onepage&q=Reynolds%20boundary%20conditions%20in%20the%20circumferential%20direction&f=false
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