Meshgrid Error in Python

Newby here. I am having trouble with manipulating my grid after i use the meshgrid. The code is as follows:

def XV(v):
return v**2

"Create the points over v and u"
v = linspace(-10,10,20)
u = np.random.normal(0,10,20)

"create the grid"
V, U = meshgrid(v,u)

"Create the order flow Y"
Y = XV(V) + U

"Create joint probability function"

def FVY(Y,XV,V):
    return (1/2*pi)*exp(-((Y-XV(V))/2))*exp(-(V**2)/2)

There is no error in the creation of Y, but when I go to create FVY I get the following error.

TypeError: only length-1 arrays can be converted to Python scalars 

As far as I can see there is nothing different in the construction of these two variables and so I can't understand the error.

Thanks for any help.