circuit help

i have attached my circuit and corresponding waveform,i don't even know what my attached circuit is called as.i have 5vrms ac source c, 3v dc source ,some k ohm resistor , all are connected in series.my output waveform look like its shifted down.what operation actually going on there and how the waveform shifted down.Thank you in advance

The 3 volt battery (or supply) pushes the signal down by 3V.
If you reverse the battery it will shift up by 3V.

I agree, all you are doing by adding the 3V dc source is creating a dc offset, as Ron said, the polarity of which will depend on which way round the dc source connected