A calibration device , comprising: a tank which, in operation, contains a temperature-controlled fluid, the tank including a bottom wall and a plurality of side walls , the side walls including a first side wall having a first surface that forms a first obtuse angle with a surface of the bottom wall , and a second side wall having a first surface that forms a second obtuse angle with the surface of the bottom wall ; wherein the first side wall is opposite the second side wall , wherein each of the first surface of the first side wall , the first surface of the second side wall , and the surface of the bottom wall is flat, and wherein the first surface of the first side wall is longer than the first surface of the second side wall such that a distance from the surface of the bottom wall to an end of the first surface of the first side wall farthest from the surface of the bottom wall is greater than a distance from the surface of the bottom wall to an end of the first surface of the second side wall farthest from the surface of the bottom wall ; a motor ; a fluid propulsion device coupled to the motor , the fluid propulsion device being disposed inside the tank opposite the first surface of the first side wall ; and a heater circuit which, in operation, generates heat within the tank , wherein, while the fluid propulsion device rotates in a predetermined direction, the fluid propulsion device is arranged to move the temperature-controlled fluid that is disposed in the tank and heated by the heater circuit toward the first surface of the first side wall such that some of the fluid heated by the heater circuit deflects off the first surface of the first side wall and some of the fluid heated by the heater circuit travels across a lower portion of the tank and deflects off of the first surface of the second side wall . a tank which, in operation, contains a temperature-controlled fluid, the tank including a bottom wall and a plurality of side walls , the side walls including a first side wall having a first surface that forms a first obtuse angle with a surface of the bottom wall , and a second side wall having a first surface that forms a second obtuse angle with the surface of the bottom wall ; wherein the first side wall is opposite the second side wall , wherein each of the first surface of the first side wall , the first surface of the second side wall , and the surface of the bottom wall is flat, and wherein the first surface of the first side wall is longer than the first surface of the second side wall such that a distance from the surface of the bottom wall to an end of the first surface of the first side wall farthest from the surface of the bottom wall is greater than a distance from the surface of the bottom wall to an end of the first surface of the second side wall farthest from the surface of the bottom wall ; a motor ; a fluid propulsion device coupled to the motor , the fluid propulsion device being disposed inside the tank opposite the first surface of the first side wall ; and a heater circuit which, in operation, generates heat within the tank , wherein, while the fluid propulsion device rotates in a predetermined direction, the fluid propulsion device is arranged to move the temperature-controlled fluid that is disposed in the tank and heated by the heater circuit toward the first surface of the first side wall such that some of the fluid heated by the heater circuit deflects off the first surface of the first side wall and some of the fluid heated by the heater circuit travels across a lower portion of the tank and deflects off of the first surface of the second side wall . <EOS>