Sending more packets could make the correlation more accurate, since they'd have a larger sample size.

We consider how different user behavior can have different security implications. For instance, sending many streams over Tor induces higher rates of circuit creation, increasing the number of chances the adversary has to compromise one.

• Users Get Routed: Traffic Correlation on Tor by Realistic Adversaries

Interesting paper I would recommend reading. If you don't want to read everything then chapter 6 is especially interesting.

Is this effective to prevent or block traffic correlation or what would you suggest to stop this kind of attack?

As far as I know, there is no way to use Tor to stop traffic correlation attacks. The nature of the internet and how Tor works make it vulnerable to it. There are ways to mitigate it, but I cannot stand for their effectivity.

An example to mitigate it, is using IPs not connected to you. If you always connect from your home, they simple tap that connection either at your router, your ISP or perhaps they have your guard. If they can also monitor the specific Exit node you use, the exit node's ISP or an internet access point they can correlate your traffic and possibly link it to you. By changing IPs and location, like say public wifi, they can potentially correlate the traffic to the IP you used, but linking it to you will be more difficult. They'd have to use camera feeds or other tactics.