OpenLayers3: How to reload a layer from GeoServer when underlying data change?

(I have asked this at SO but didn't receive much response, so I am asking it here. Sorry about the cross-posting).

I have a webpage that displays a GeoTIFF served via GeoServer as an OpenLayers3 ImageWMS. What I need is to (via a button) reload the OL3 layer after the underlying GeoTIFF changes.

I searched around, and tried

layer.dispatchChangeEvent();

on the layer in question. But the map/image isn't updated.

I have also tried removing the layer, constructing a new layer and add it back. It didn't work either.

The only thing that works is to reload the whole webpage, in which case the map shows the new image but all states in the page is lost.

My question is

How can I reload the layer without having to reload the whole page?

Thanks