Use the following css to move the project title on top of the image on hover.

.et_pb_filterable_portfolio .et_pb_portfolio_item h2 {
position: absolute;
text-align: center;
top: 55%;
width: 100%;
opacity: 0;
}
.et_pb_filterable_portfolio .et_pb_portfolio_item:hover h2 {
opacity: 1;
z-index: 99;
}
Code language: CSS (css)