I built and ran the following simple program:

#include <iostream>
#include <ns3/nstime.h>

using namespace ns3;

int main (int argc, char** argv)
{
  Scalar omega = 5.0;
  Scalar tdivT = 0.5;
  Scalar result = omega * tdivT ; 
  std::cout << " expected " << omega.GetDouble() * tdivT.GetDouble()
	    << " actual " << result.GetDouble()  
	    << std::endl;
}
  

And the result I got is:

 expected 2.5 actual 0

I would expect result.GetDouble() to return the value 2.5, too.