freefoam-enstrophy: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/freefoam-enstrophy - from package: freefoam

You may install the required package with command apt-get install {package}
Error in other languages:
freefoam-enstrophy: bevel nie gevind nie
freefoam-enstrophy: comandă negăsită
freefoam-enstrophy: comando não encontrado
freefoam-enstrophy: commande introuvable
freefoam-enstrophy: command not found
freefoam-enstrophy: käsku ei ole
freefoam-enstrophy: không tìm thấy lệnh
freefoam-enstrophy: komanda nerasta
freefoam-enstrophy: Kommando nicht gefunden.
freefoam-enstrophy: kommandot finns inte
freefoam-enstrophy: komut yok
freefoam-enstrophy: nie znaleziono polecenia
freefoam-enstrophy: níor aimsíodh an t-ordú
freefoam-enstrophy: no se encontró la orden
freefoam-enstrophy: no s'ha trobat l'ordre
freefoam-enstrophy: opdracht niet gevonden
freefoam-enstrophy: parancs nem található
freefoam-enstrophy: perintah tidak ditemukan
freefoam-enstrophy: príkaz nenájdený
freefoam-enstrophy: příkaz nenalezen
freefoam-enstrophy: команда не найдена
freefoam-enstrophy: командата не е открита
freefoam-enstrophy: 命令找不到
freefoam-enstrophy: コマンドが見つかりません