FLC OF CE550 ENCOUNTER WAKE TURB JUST AS THEY ARE INTERCEPTING THE GS. AFTER REGAINING CTL; THEY ARE HIT AGAIN BY THE WAKE. AFTER CHANGING TO TWR FREQ THEY ARE INFORMED THAT THEY ARE IN TRAIL OF A B737.

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WHILE CLRED FOR APCH (ILS) AT BNA AT 3000 FT; WE WERE ABOUT TO CONFIGURE TO LAND. WE THEN ENCOUNTERED MODERATE TO SEVERE WAKE TURB THAT CAUSED THE ACFT TO ROLL APPROX 60 DEGS. WE CORRECTED; FLEW ABOVE THE GS TO A NORMAL LNDG. AFTER TOLD TO CONTACT THE TWR; WE WERE TOLD THAT WE WERE 4 MI IN TRAIL OF B737. APCH CTL NEVER INFORMED US WE WERE FOLLOWING ANY ACFT NOR DID THEY EVER TELL US TO REDUCE SPD. AFTER INFORMING TWR WHAT HAPPENED THEY APOLOGIZED. I CALLED THE TWR ON THE GND TO PASS ALONG WHAT HAPPENED AND TO NOTIFY APCH. APCH CTL SHOULD HAVE NOTIFIED US IF WE WERE IN TRAIL OF ACFT; ESPECIALLY A B737. THIS WOULD HAVE ALLOWED US TO SLOW OR PLAN TO FLY ABOVE THE GS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT TRACON DID NOT NOTIFY THEM THAT THEY WERE IN TRAIL. IT WAS NOT UNTIL THEY SWITCHED TO TWR THAT THEY WERE INFORMED OF FOLLOWING THE B737. RPTR BELIEVES THE B737 MUST HAVE BEEN BROUGHT IN FROM A HIGHER ALT AND THE WAKE SETTLED INTO THEIR PATH AS THEY WERE ABOUT TO INTERCEPT THE GS. HAD THEY BEEN AWARE THEY WOULD CERTAINLY HAVE REMAINED ABOVE GS AND SLOWED THEIR SPD. MOST OF THE TIME CTLRS ARE GOOD ABOUT NOTIFYING OF TFC AHEAD SO ONE CAN PLAN.