title: Sinus Function Changing Temperature 

This testcase gives an example of changing heat due to changing temperature.
For the changing in Temperature in space, a sinus fuction is defined. The simulation
domain is a small cube with periodic boundary conditions. 

**Features used**

1. Projection: fpt

2. Polynomial representation: Q

3. Filtering: -- 

4. Timestepping: explicitRungeKutta, 4 steps 

5. Boundary conditions: -- 

6. Others: 
   - Derived quantity: Temperature

