[ybcfd]

Hello everyone,

I have been dealing with 1D acoustic simulation of cold end exhaust line that is integrated to an encrypted diesel engine model.

My aim was to obtain graph of flow spl(sound pressure level) at the tailpipe vs rpm from the analysis and compare it with the test results.

I have created a model but the distribution shows strong difference compared to test results graph. I see spl at tail pipe decreasing after 2500 rpm till 4500 rpm while it is continuously increasing in tests.

I checked some studies that have same problem but they kinda solved it by adding the effect of jet noise(?) and obtained the spl distribution over rpm that is pretty similar with the distribution obtained from the tests.

So how can i take into account this jet noise effect for this analysis to obtain the similarity for sound pressure level of tail pipe over an rpm range?