A gas turbine engine component comprising a double-wall structure, the double-wall structure comprising: a first wall having a first surface and a second surface; a second wall spaced apart from the first wall such that the second surface of the first wall faces the second wall, the second wall comprising at least one cooling fluid orifice configured to direct cooling fluid in the direction of the first wall; and at least one protrusion extending from a base on the second surface of the first wall to a tip, wherein: the or each protrusion corresponds to a respective cooling fluid orifice and is located such that a line that passes through the tip of a given protrusion and which is normal to the second surface passes through the respective cooling fluid orifice such that, in use, cooling fluid from its respective cooling fluid orifice is directed towards its tip, with substantially all cooling fluid that is directed towards the tip of any given protrusion being from its corresponding respective cooling fluid orifice such that the cooling fluid follows the external shape of the protrusion 50 as it moves from the tip 54 to the base 52; and the height (h) of the protrusion above the second surface is at least 25% of the distance (w) between the first wall and the second wall. a first wall having a first surface and a second surface; a second wall spaced apart from the first wall such that the second surface of the first wall faces the second wall, the second wall comprising at least one cooling fluid orifice configured to direct cooling fluid in the direction of the first wall; and at least one protrusion extending from a base on the second surface of the first wall to a tip, wherein: the or each protrusion corresponds to a respective cooling fluid orifice and is located such that a line that passes through the tip of a given protrusion and which is normal to the second surface passes through the respective cooling fluid orifice such that, in use, cooling fluid from its respective cooling fluid orifice is directed towards its tip, with substantially all cooling fluid that is directed towards the tip of any given protrusion being from its corresponding respective cooling fluid orifice such that the cooling fluid follows the external shape of the protrusion 50 as it moves from the tip 54 to the base 52; and the height (h) of the protrusion above the second surface is at least 25% of the distance (w) between the first wall and the second wall. the or each protrusion corresponds to a respective cooling fluid orifice and is located such that a line that passes through the tip of a given protrusion and which is normal to the second surface passes through the respective cooling fluid orifice such that, in use, cooling fluid from its respective cooling fluid orifice is directed towards its tip, with substantially all cooling fluid that is directed towards the tip of any given protrusion being from its corresponding respective cooling fluid orifice such that the cooling fluid follows the external shape of the protrusion 50 as it moves from the tip 54 to the base 52; and the height (h) of the protrusion above the second surface is at least 25% of the distance (w) between the first wall and the second wall.