******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Hello, I am using the Acoustic solver to solve Linearized Euler Equations. I wish to use a sponge region in my setup. I have gone through the user guide and test cases but I am unable to understand how the coefficients are actually being applied in the sponge region. If I refer to Sec 3.6.1 of the v5.5.0 user guide, it says that the coefficient's values can be defined using the variable "r" and this variable can be used to control the distance to the sponge region. So, are we specifying the distance to the sponge region or, the values of coefficients in the sponge region ? If it's the former, does it mean that damping of waves will automatically be applied by Nektar++? I set-up a very simple 1D initial-value problem where a Gaussian pulse placed at the centre of -100 <= x <= 100 travels in left-right direction. I set-up the evaluation of "r" as a linear increase from -0.2 to 0 from x=60 to x=100. I was expecting that the pulse in the right will completely vanish as it reaches x=100. This was however not the case. I assumed that the amplitude of the pressure pulse will be multiplied by the values from -0.2 to 0. Can someone please provide some clarity on this ? Regards, Ishan PGR