A flanger could do it really well too
Eh . . . I mean, you could get a kind of pulsing with a flanger but it would be much more metallic sounding and jet engine whooshy. Flanging always seems like it's sitting prominently right on top of the sound of a guitar, where phasing effects kind of blend better to my ears.
Sounds more like a rotary/leslie effect to me. Check out some videos of the mini vent II and you'll hear it right away.
You could get close with a univibe or foot controlled phaser with subtle settings though.
Looks like rotary effects are prohibitively expensive for my minimal need, but could consider just getting a Phase 95
Thanks all
tthe ventilator is great and still in production
a vibrato and flanger set to the same speed .
I'm intrigued. That's a great idea.