Substitute keys for a mouse wheel

I have a sailing simulator which requires the mouse wheel to perform some functions. Since I'm playing on a laptop, there isn't any wheel. I tried some
combinations of keys which don't work. Can somebodi suggest me the equivalent
of the mouse wheel? Thanks a lot, Paolo.

 

The basic function of a wheel is to scroll up and down. The up and down arrow keys on the keyboard perform that same function.

 

Need system specs. Laptop with touch pad? many touchpads have software which allow you to set options for for your touchpad. Many touchpads have the far right side set up to function as a wheel scroll.

Software soultions?????
A software designed to set options with many touchpads.
See this for example:
http://majorgeeks.com/Synaptics_Touchpad_Driver_d4913.html

Second option is, of course, to disable touchpad and get plugin mouse (usb or serial).

The simulator it self may have options to set controls or keybord substutes keys which function for mouse movement. Many use w a s d for up left right and down.