Will wind tunnel modelling ever be completely replaced by computer models?
The thing about computer models is that they are just that; models. They can only approximate the actual behavior we see in the real world.

Computer models are good for trying many different ideas and making predictions. It can be faster to create a new computational test than to make a physical model for a wind tunnel. But very detailed fluid dynamics calculations require large amounts of computing power, and this takes time and money as well.

Wind tunnels can give much more detailed and accurate information, and are useful for validating the results given by the computers. The results don't always match, which means that the computer models must be revised. This is where wind tunnels are still very useful. They can test an entire airplane in actual flow, where computing that detail across the whole aircraft would require long computations.

Although a wind tunnel is also only a model of real conditions, it provides an actual body in actual flow conditions, which means the results can correlate much more closely to the real conditions being tested. Computational analysis is limited by assumptions, the chosen modeling method, and computational power.

Until computing power reaches the point where it can run models that will truly match a wind tunnel's accuracy and detail, there will still be a need to use wind tunnels to provide data.